Home » Blog

Too Much of a Good Thing

Submitted by Amy Sercel MS RD CD

Edited by Marcia Bristow MS RDN CSSD CD

Every health guideline seems to come with the recommendation to increase physical activity levels. It’s widely understood that getting enough activity boosts mental health, can help keep your immune system strong, and decreases your risk of chronic diseases like cancer, diabetes, osteoporosis, and heart disease. Public health officials estimate that 50-80% of the United States population falls short of the guideline to get at least 30 minutes of moderate-intensity exercise each day, for a total of at least 150-300 minutes per week.1 What about the other end of this continuum though? Is it possible to get too much exercise?

Although it is difficult to find a safe maximum amount of exercise recommended in the Physical Activity Guidelines for Americans, one study suggests that this amount may be no more than 60-90 minutes of endurance exercise per day, five days per week. At higher levels than this, the health benefits of being active actually start to decrease.2

Relative Energy Deficiency in Sport (RED-S)

Excessive exercise impacts every system in your body when you are not eating enough to fuel both physical activity and the body’s basic functions. These functions include the immune system, digestion, heart rate, and reproductive system. When RED-S occurs, the body slows down these processes in an effort to reduce overall energy expenditure. As a result, athletes who exercise excessively without eating enough to replace the calories they burn have:3

  • A higher risk of injury (such as stress fracture)
  • Difficulty concentrating due to lack of fuel for the brain
  • Feelings of depression or anxiety
  • Constipation due to slowing of the digestive system
  • Reproductive dysfunction seen as loss of menstrual cycle in females or low testosterone in males

Any athlete who engages in prolonged endurance activity on a regular basis is at risk for RED-S because they may not realize how much more they need to eat in order to make up for the energy burned during activity. Elite athletes and people training for long-distance endurance events, such as marathons or triathlons, are also at a higher risk for RED-S. Fortunately, most of the health impacts of RED-S reverse when an athlete reduces their activity level and/or begins eating enough to fuel their activity.

Cardiovascular Effects

While RED-S is one of the more immediate consequences of excessive exercise, in the long term excessive exercise can increase the risk of heart disease.

Endurance exercise causes the heart to beat more quickly. At high levels, this leads to changes in the heart’s structure that can cause heart arrhythmias, or an irregular heart beat.2,4 This in turn raises the risk of heart attack, stroke, and sudden death. For this reason, it’s suggested that lower amounts of running have the most positive impact on heart health, and researchers advise limiting vigorous endurance exercise to no more than 1 hour per day, 5-6 days per week.2

What’s the Right Amount?

While there are risks of excessive exercise, the health benefits of regular physical activity are indisputable. If you are working on increasing your activity level to promote your own health, aim for about 30 minutes of moderate-intensity activity per day. One study found that this exercise level was associated with the lowest risk of heart disease.2

If you are already highly active as an endurance athlete, make sure you are fueling your body properly by eating enough on a day-to-day basis and including good sources of energy before, during, and after workouts. If you’d like support with this, meet with a registered dietitian who can help you create a nutrition plan to complement your training. If you have a history of intense endurance exercise, it’s also important to have regular check-ups with your doctor, who can monitor your heart health over the long term.


  1. Physical Activity for Everyone: Guidelines: Adults | DNPAO | CDC. http://www.cdc.gov/physicalactivity/everyone/guidelines/adults.html. Accessed June 14, 2015.
  2. Lavie CJ, O’Keefe JH, Sallis RE. Exercise and the Heart — the Harm of Too Little and Too Much. Curr Sports Med Rep. 2015;14(2):104. doi:10.1249/JSR.0000000000000134
  3. Mountjoy M, Sundgot-Borgen J, Burke L, et al. The IOC consensus statement: beyond the Female Athlete Triad—Relative Energy Deficiency in Sport (RED-S). Br J Sports Med. 2014;48(7):491-497. doi:10.1136/bjsports-2014-093502
  4. Kim Y-J, Kim C-H, Park K-M. Excessive exercise habits of runners as new signs of hypertension and arrhythmia. Int J Cardiol. 2016;217:80-84. doi:10.1016/j.ijcard.2016.05.001

A2 Milk: Healthy or Hype?

Submitted by Sarah Lange

Edited by Marcia Bristow MS RDN CSSD CD

If you take a trip to your local grocery store, you will likely find A2 milk in the dairy coolers. A half-gallon of A2 milk is 85% more expensive than the conventional milk on the neighboring shelf, so what is all the hype and is it worth the price? There are many different nutrition crazes and fads circulating on the internet, in magazines, and on social media, and A2 milk is just one of the latest trends to hit the market. A2 milk is milk that contains a specific type of protein and is supposedly easier to digest. Who would have guessed that the genetic makeup of the cows your milk comes from would be one of the newest crazes?

Casein, the largest group of proteins in milk, accounts for about 80% of the total protein content. While there are several types of casein found in milk, beta casein is one of the most common forms. Beta-casein exists mainly in the A1 and A2 forms.1 Regular cow milk, that you would find in any grocery store, contains a mixture of both A1 and A2 beta-casein. The ratio of Al to A2 depends on the type of cow the milk comes from, but it is generally about 50/50.1

Before cows were domesticated, they only produced A2 beta-casein protein. At some point after they were domesticated, a natural mutation occurred of a single gene in Holstein cows, resulting in the production of A1 beta-casein.1 While milk from some types of cows, such as Jersey cows, still contains mostly A2 beta-casein, milk from Holsteins contains mostly A1. The most common dairy cow breed in Australia, Northern Europe, and the United States is the Holstein, meaning most milk on grocery stores shelves contains A1 beta-casein.1

Since A1 and A2 proteins are built slightly differently, it is thought that they differ in digestibility. Given the structure of the A2 protein, it may be easier to digest. Scientists believe that the structure of the A2 protein is easier for everyone to digest, but may be especially beneficial for those who are lactose intolerant.2 One of the byproducts of A1 protein, beta-casomorphin (BCM-7), is believed to cause inflammation, which could be a main contributor to gastrointestinal problems.1 While scientists agree on the structural differences between A1 and A2 proteins and that the structure of the A2 protein makes it easier to digest, the research is just beginning on the impact of these variations on the human body and, thus far, the evidence of any health benefits remains unclear.

The a2 Milk Company, and others, have capitalized on the prospects of A2 milk providing gastrointestinal relief for consumers who find regular milk difficult to digest. Many people who have difficulty digesting milk think it is because of the lactose, but it is possible that their symptoms could be from the A1 proteins.2 However, the evidence on this claim is sparse. The a2 Milk Company funded a study in China in which 600 adults who reported lactose intolerance were randomly assigned to drink either regular milk or A2 milk. Participants drinking the A2 milk reported less severe bloating, gas, and abdominal pain, but only slightly less than the participants drinking the A1 milk.2

The bottom line is that the science either isn’t there yet to support the health benefit claims of A2 milk or the benefits simply do not exist. Until more research is conducted, and not funded by A2 milk companies, it is probably not worth doling out the extra cash for A2 milk.


  1. Truswell AS. The A2 milk case: a critical review. Eur JClin Nutr. 2005;59(5):623-631. doi:1038/sj.ejcn.1602104
  2. He M, Sun J, Jiang ZQ, Yang YX. Effects of cow’s milk beta-casein variants on symptoms of milk intolerance in Chinese adults: a multicentre, randomised controlled study. Nutr J. 2017;16(1):72. doi:1186/s12937-017-0275-0
  3. Image from: www.happymilk.in/a1-vs-a2-milk/

Take your Coffee with Cream, Sugar… or Butter?

Submitted By Amy Sercel MS RD CD

Edited By Marcia Bristow MS RDN CSSD CD

You can spot a fad diet by the number of unique products or supplements you need to buy to follow the diet as “completely” as possible. The ketogenic diet is arguably the most popular fad diet right now. You can read more about it in our earlier blog post. In short, the ketogenic diet is a very high-fat diet that involves eating no more than about 3 servings of carbohydrate-rich foods per day. This shifts your body away from burning carbohydrates for fuel, and instead forces your body to convert fats into a compound called ketones that your cells can use for fuel instead of carbohydrates.

Right now, there is no shortage of foods, supplements, and other products you can buy to help “push you into ketosis,” prevent digestive distress, or help you get through the “keto flu” more quickly. One product you may have heard of is called Bulletproof Coffee.

Bulletproof Coffee is freshly brewed coffee (ideally made in a French press) blended with about two tablespoons of medium chain triglyceride (MCT) oil and 1-2 tablespoons of butter or ghee.1 Altogether, this comes to about 500 calories and 38 grams of saturated fat.2 For comparison, consider that a person who eats 2,000 calories per day is recommended to get no more than 22 grams of saturated fat in one day.

People have been lightening their coffee and tea with butter for hundreds of years, specifically people living in Nepal, India, Ethiopia, Vietnam, and Singapore. In Ayurvedic cultures, butter tea is thought to “improve mental alertness and cognitive capacity.”3 Fortifying coffee and tea with butter may also provide additional fuel required for life in inclement environments or at high altitudes that naturally increase metabolic rate.

In Western culture, butter coffee has taken off due to its compatibility with the ketogenic diet. According to the website, Bulletproof products are intended to enhance cognitive and physical performance. The makers of Bulletproof Coffee argue that adding grass-fed butter to your coffee will provide you with “high-quality fats that help keep you full and fueled.” Their “Brain Octane Oil” contains MCTs derived from coconut oil. According to the website, this is more effective than regular coconut oil at pushing your body into ketosis. You can buy a kit that contains 12 ounces of coffee, a bottle of MCT oil, and a bottle of grass-fed ghee for about $50 to get started.1

The problem is there isn’t any significant evidence proving that supplementing with MCT oil or following the ketogenic diet are more effective for promoting long-term health. The ketogenic diet was originally intended as a treatment for epilepsy. Studies have shown that up to 50% of these people following the ketogenic diet end up with elevated triglycerides and LDL cholesterol (the “bad” kind), increasing the risk of heart disease.4 Other studies suggest that high-fat diets might promote tumor growth, and diets high in saturated fat promote the storage of fat around your organs.5 On the other hand, diets higher in unsaturated fat tend to decrease your risk of heart disease. Diets that contain carbohydrates from whole grains, fruits, and vegetables have been shown to decrease inflammation compared to high-fat diets, and increase satiety.5 In contrast, high-fat diets increase satiety but also increase inflammation.

Many people recommend switching to MCT oil instead of other types of fats to promote weight loss, claiming that it helps promote satiety by increasing ketone formation. This claim is also not proven. One study showed that people supplementing with MCT oil only lost 0.5 kg more over 10 weeks than people on a regular weight loss diet.6 Half a kilogram (about 1 pound) could be attributed to differences in hydration status and does not indicate more success with long-term weight loss.

All in all, Bulletproof Coffee aims to capitalize on a fad diet without any evidence that it will do anything besides keep you in ketosis. While this might promote weight loss in the short term, there are no studies showing the ketogenic diet is any more effective for weight loss after about 1 year. You may be putting yourself at risk for developing heart disease, and also risk nutrient deficiencies by cutting out food groups rich in vitamins, minerals, antioxidants, and fiber. At the very least, you risk wasting money on a fad that is unlikely to make your life better in the long run.


  1. Official Bulletproof Coffee Recipe – With Video. https://www.bulletproof.com/blogs/recipes/official-bulletproof-coffee/. Accessed May 27, 2019.
  2. Can butter coffee jump-start your morning? – Nutrition Action. https://www.nutritionaction.com/daily/brain-health/can-butter-coffee-jump-start-your-morning/. Accessed May 27, 2019.
  3. Tradition Turned Trendy: Exploring the Origins of Butter Beverages – Food & Nutrition Magazine. https://foodandnutrition.org/january-february-2015/tradition-turned-trendy-exploring-origins-butter-beverages/. Accessed May 27, 2019.
  4. CPE Monthly: The Ketogenic Diet for Epilepsy – Today’s Dietitian Magazine. https://www.todaysdietitian.com/newarchives/0516p46.shtml. Accessed May 27, 2019.
  5. Dietary fat: From foe to friend? | Science. https://science.sciencemag.org/content/362/6416/764. Accessed May 23, 2019.
  6. Mumme K, Stonehouse W. Effects of Medium-Chain Triglycerides on Weight Loss and Body Composition: A Meta-Analysis of Randomized Controlled Trials. J Acad Nutr Diet. 2015;115(2):249-263. doi:10.1016/j.jand.2014.10.022


Submitted by Amy Sercel MS RD CD

Edited by Marcia Bristow MS RDN CSSD CD

Marijuana has recently been legalized for either medical or recreational use in many states.  Many people are now exploring cannabis-derived products to treat a wide variety of conditions, including (but not limited to) anxiety, arthritis, chronic pain, inflammation, muscle spasms, seizures, and insomnia.1,2 People looking for something to help manage one of these conditions without the intoxicating effect of marijuana often turn to CBD.

CBD, or cannabidiol, is the second-most prevalent compound in the marijuana plant behind THC (tetra-hydrocannabidiol, the psychoactive compound).  CBD is also present in hemp plants, which do not contain THC.  Hemp-based CBD oil is legal in every state, and is often added to tinctures, pills, salves, and even baked goods or energy bars.1,2 The World Health Organization recently reported that CBD has not been associated with addiction or dependence because it does not create the “high” that occurs with the use of THC.2

Both CBD and THC act by stimulating the endocannabinoid system.  This system is made up of neurotransmitters and endocannabinoid receptors in the brain, spinal cord, and peripheral neurons throughout the body.  The activation of endocannabinoid receptors can influence mood, cognition, appetite, pain, blood pressure, digestion, and inflammation, among many other essential processes.3

Although people use CBD to manage a wide variety of ailments, so far there is only strong evidence that CBD can effectively treat seizures.4 A medication called Epidiolex, which contains CBD, was recently approved by the FDA and can now be prescribed to treat two different types of epilepsy.5 Other than that, small-scale studies and case reports indicate that CBD is also a successful treatment for insomnia and anxiety, and has been shown to reduce pain in animals when used topically.2,6 However, more long-term, large-scale studies in humans are needed to determine whether CBD truly does alleviate all of the conditions it has been associated with.

One of the most significant problems with CBD is the lack of dosing recommendations.  Studies suggest that humans can safely tolerate up to 1500 mg of CBD each day, but a daily dose of 100 mg CBD has been shown to reduce seizure frequency in children and adolescents.  In one patient, a 5-month course of just 25 mg of CBD per day helped improve sleep quality and reduce anxiety. There are also no high-quality scientific studies that can provide guidance on how long someone should continue using CBD after their symptoms improve.4,6,7

In addition, CBD is currently treated as a supplement, not a medication, and as such there is little to no regulation of a product’s quality or CBD content.  Although CBD itself is not associated with any negative health impacts, there is a risk that products containing CBD may be contaminated with harmful substances, including pesticides or molds.  A study in the Netherlands recently found that many CBD products also contained THC, and some did not actually contain any CBD at all.7

Given the widespread popularity of CBD products, all of this suggests that there is an urgent need for more studies on the effectiveness of CBD so people can be sure they are using it in the correct dosages.  Additionally, there is a need for more specific testing to guarantee the purity and CBD content of all CBD products available for purchase.  If possible, look for CBD products that have been tested by a third party organization to determine the amount of CBD they contain. In Vermont, the store Ceres Natural Remedies can perform a lab analysis of hemp and marijuana products to determine their CBD and THC content.  Hemp producers who have paid for this analysis should be able to provide the results to their customers.  The Ceres Natural Remedies store is affiliated with the state’s medical marijuana dispensary and certifies products sold there, in addition to other hemp products sold throughout the state.8,9 Although there does not appear to be a risk of dependence and there is no risk of intoxication from CBD alone, it can interact with certain medications (such as Coumadin), so be sure to inform your doctor if you use CBD.


  1.  Ask the Expert: Spotlight on Cannabidiol – Today’s Dietitian Magazine. https://www.todaysdietitian.com/newarchives/0618p8.shtml. Accessed April 8, 2019.
  2.  Cannabidiol (CBD) — what we know and what we don’t – Harvard Health Blog – Harvard Health Publishing. https://www.health.harvard.edu/blog/cannabidiol-cbd-what-we-know-and-what-we-dont-2018082414476. Accessed April 8, 2019.
  3.  Endocannabinoids: Overview, History, Chemical Structure. https://emedicine.medscape.com/article/1361971-overview. Accessed April 15, 2019.
  4.  Halford J, Marsh E, Mazurkiewicz-Beldzinska M, et al. Long-term Safety and Efficacy of Cannabidiol (CBD) in Patients with Lennox-Gastaut Syndrome (LGS): Results from Open-label Extension Trial (GWPCARE5) (P1.264). Neurology. 2018;90(15 Supplement):P1.264.
  5.  Epilepsy Foundation Statement on DEA’s Scheduling of Epidiolex® Philip M. Gattone, President and Chief Executive Officer, Epilepsy Foundation. Epilepsy Foundation. https://www.epilepsy.com/release/2018/9/epilepsy-foundation-statement-dea%E2%80%99s-scheduling-epidiolex%C2%AE-philip-m-gattone-president. Accessed April 22, 2019.
  6.  Shannon S, Opila-Lehman J. Effectiveness of Cannabidiol Oil for Pediatric Anxiety and Insomnia as Part of Posttraumatic Stress Disorder: A Case Report. Perm J. 2016;20(4). doi:10.7812/TPP/16-005
  7.  Hazekamp A. The Trouble with CBD Oil. Med Cannabis Cannabinoids. 2018;1(1):65-72. doi:10.1159/000489287
  8.  Baird JB. Test the potency of your homegrown VT weed. Burlington Free Press. https://www.burlingtonfreepress.com/story/news/2018/06/12/vermonters-can-legally-test-cannabis-potency/659507002/. Published June 12, 2018. Accessed April 22, 2019.
  9.  Lab Analysis of CBD Content – Green Mountain Hemp Company. Vermont CBD Hemp Products: Green Mountain Hemp Company. https://www.greenmountainhempcompany.com/lab-analysis/. Accessed April 22, 2019.

The Keys for Muscle Building

Submitted by Amy Sercel MS RD CD

Edited by Marcia Bristow MS RDN CSSD CD

“If some is good, more is better,” is an all-too-common trap, not least in the nutrition world.  Many people apply this idea to their food choices, especially when they’re trying to use their diet to enhance physical performance.  Many athletes include very large portions of protein-rich foods throughout the day to achieve muscle growth or boost their strength.  It turns out that an extremely high protein intake is really not necessary to get the results you may be looking for.

The average, minimally active adult needs about 0.8 grams of protein per kilogram of body weight to maintain overall health.  For a 150-pound person, this translates to a total of 55 g protein per day.  Some athletes more than triple that intake in an effort to build muscle, eating 3-3.5 grams of protein per kilogram of body weight each day!1 These athletes are far exceeding their protein needs, and may be putting their health at risk.  In general, athletes need about 1.2-1.7 grams of protein per kilogram of weight to maintain muscle mass, or about 81-115 grams for a 150-pound athlete.  Ammonia is produced as a byproduct of protein breakdown, and when someone eats more than 2.5 grams of protein per kilogram of body weight each day, they risk maxing out their body’s capacity to safely get rid of that ammonia, which could lead the ammonia to build up in their blood.1

In reality, someone who is trying to build muscle can expect to gain, at most, about 1 pound per week.  If this is a goal for you, you only need an extra 14 grams of protein per day.  This means the 150-pound athlete would need 95-130 grams of protein per day to build muscle.  An extra 14 grams of protein could come from 2 hard-boiled eggs, 2 oz of poultry or beef, 12 fluid ounces of milk, or ¾ cup of tofu.  At the same time, you’ll need about 400 extra calories per day, on top of what you need to maintain your current weight and activity level, to support muscle tissue growth, because muscle building itself requires energy.1,2 

If you don’t know your daily calorie needs, you can use this calculator to get an estimate.  Once you’ve learned the amount you need to eat to maintain your weight and activity level, add about 400 calories to support muscle gain.  Since you’ll need an extra 14 grams of protein, about 60 of these calories should come from protein.

A protein-rich post-workout meal or snack will help you build muscle mass by ensuring that your body has the building blocks available when muscle synthesis is triggered.  In one study, researchers compared the muscle mass of a group who consumed 10 grams of protein immediately after exercise and another group who had no post-exercise nutrition.  The group who ate a post-exercise snack gained muscle, while the group who didn’t lost muscle by the end of the study.2

Your diet is only half of the equation though.  In order to trigger muscle growth, you also need to engage in some type of strength training.  During strength training, the force on your muscles activates the genes that regulate muscle synthesis and trigger them to start making new muscle fibers.1 Once they’re activated, your body will use the energy and protein from your diet to build muscle.  If you don’t have enough energy or protein available, your body will be unable to repair the tears that occurred during your strength workout, and you will likely experience some muscle loss.1,2

There isn’t a clear consensus on the type of strength training that will result in the most significant muscle gains.  This is partially because muscle increases depend so much on individual body type, hormone levels, and genetics.1 Some people recommend using higher weights and lower repetitions, while others suggest that the opposite type of lifting may be more effective.  One small-scale study of 15 men found that low-weight, high repetition training had a stronger impact on muscle growth because the cellular signals triggering muscle growth remained active 24 hours after the weight training session, while they only remained active for about 4 hours after the high-weight, low repetition session.3 More studies with a larger participant pool are needed before we can say for certain whether this advice applies to the entire population.

Another study examined frequency of training and found that people who completed nine sets (or cycles of unique exercises) over three days of the week gained the same amount of muscle as those who did all nine sets on one day and didn’t do any other strength training during the week. The researchers concluded that the total volume of training was more important for muscle growth than the frequency throughout the week.4

The main take-away is, if you want to build muscle you don’t need to take extreme measures in your diet and exercise.  Incorporate weight lifting into your typical workout routine each week, and make sure to include a post-workout meal or snack that contains a good source of protein.  Get an idea of the amount you need to eat to maintain your current weight, and add an extra 400 calories to that to support muscle growth.  If you’d like more support with meal planning and timing your nutrition around activity, or if you’ve made changes but aren’t seeing the results you expected, meet with a registered dietitian who can give you more specific, individualized advice.  The key to this long-term change is to stick with it and remember muscle growth won’t occur overnight. Be patient!


  1.  Dunford M, Doyle JA. Nutrition for Sport and Exercise. 3rd ed. Cengage Learning; 2015.
  2.  Weinert DJ. Nutrition and muscle protein synthesis: a descriptive review. J Can Chiropr Assoc. 2009;53(3):186-193.
  3.  Burd NA, West DWD, Staples AW, et al. Low-Load High Volume Resistance Exercise Stimulates Muscle Protein Synthesis More Than High-Load Low Volume Resistance Exercise in Young Men. PLOS ONE. 2010;5(8).
  4.  Thomas MH, Burns SP. Increasing Lean Mass and Strength: A Comparison of High Frequency Strength Training to Lower Frequency Strength Training. Int J Exerc Sci. 2016;9(2):159-167.

Fast Until Your Cells Eat Themselves

Submitted by Amy Sercel MS RD CD

Edited by Marcia Bristow MS RDN CSSD CD

Intermittent Fasting has recently become popular as a method to lose weight and reduce the risk of diseases like diabetes, heart disease, and cancer.  While there are very few studies examining Intermittent Fasting’s effectiveness in humans,1 many studies in mice and rats suggest that it does lead to health benefits.  One explanation for this is Intermittent Fasting’s impact on autophagy.

Autophagy, or “self-eating,”2 describes the process in which your cells break down proteins or other structures and recycle them into new cellular components.  This process is an essential defense mechanism for your cells and naturally occurs in all healthy people.  Your cells trigger autophagy to prevent tumor growth in some cancers, destroy damaged cellular materials, and eliminate infectious bacteria or viruses.1–4 Studies show that autophagy increases in response to stress, such as the stress that occurs when you’re deprived of energy.  This makes sense, since low energy intake means that your cells aren’t consistently given the building blocks they need to make new molecules for survival.  Instead, they’re forced to recycle old, damaged, or unusable materials to create the components that keep them functioning.2

Both fasting (going 24-48 hours without eating) and calorie restriction (eating 10-40% fewer calories than usual while making sure to meet your vitamin and mineral needs) have been shown to increase autophagy throughout the body.2,3 Researchers are currently working to determine how this may translate into actionable advice, especially when it comes to preventing and treating diseases.  Some studies in mice suggest that chemotherapy may become more effective against cancer cells during Intermittent Fasting; however, it’s still unclear which types of chemotherapy work best when combined with Intermittent Fasting.3 Similarly, it’s thought that neurodegenerative diseases like Alzheimer’s and Parkinson’s are partially caused by a disruption of autophagy in the brain.  While one study showed that fasting did improve autophagy in the brains of mice with these diseases, it was unclear whether this was enough to show any improvement in symptoms.2

Lastly, since Intermittent Fasting is still relatively new, more research is needed to determine what degree is even safe.  Some studies have shown that just one 24-hour fast per month may protect against heart disease and diabetes,1 but many online articles, blogs, and social media posts suggest fasting as frequently as two or three days per week.  Fasting too often will push your body into starvation mode, causing slowed metabolism, decreased immune system, difficulty thinking straight, and many other health problems.  A study in rats also showed that chronic starvation actually prevents autophagy and damages brain cells,4 which is completely counterproductive if your goal is to boost autophagy.

Until more research is done in humans, it is best to err on the side of caution.  Choose a balanced diet that meets your needs for vitamins and minerals without providing excessive calories.  Eat when you’re hungry, and stop when you are comfortably full, not stuffed.  Many studies support the health benefits of a meal pattern rich in unprocessed foods, whole grains, lean protein, fruits, and vegetables; eating this way will keep you as healthy as possible while still allowing you to enjoy your meals every day.


  1.  Horne BD, Muhlestein JB, Anderson JL. Health effects of intermittent fasting: hormesis or harm? A systematic review. Am J Clin Nutr. 2015;102(2):464-470. doi:10.3945/ajcn.115.109553
  2.  The effect of fasting or calorie restriction on autophagy induction: A review of the literature – ScienceDirect. https://www-sciencedirect-com.ezproxy.uvm.edu/science/article/pii/S1568163718301478. Accessed March 11, 2019.
  3.  Antunes F, Erustes AG, Costa AJ, et al. Autophagy and intermittent fasting: the connection for cancer therapy? Clinics. 2018;73. doi:10.6061/clinics/2018/e814s
  4.  Alirezaei M, Kemball CC, Flynn CT, Wood MR, Whitton JL, Kiosses WB. Short-term fasting induces profound neuronal autophagy. Autophagy. 2010;6(6):702-710. doi:10.4161/auto.6.6.12376

Debunking Fad Diets

Submitted by Amy Sercel MS RD CD

Edited by Marcia Bristow MS RDN CSSD CD

After the new year we’re reminded of the “great new diets” that will make this the year to reach our goals.  With so many trends on social media, in health magazines, and sometimes even recommended by medical professionals, it can be difficult to sort through the clutter of fact vs. fiction.

If you find yourself wondering, “Do any of these diets even work?” you are not alone!  In this post, we have highlighted some of the most common diet trends you’re likely to keep hearing about in 2019.

The Ketogenic Diet

Probably the most popular fad diet right now, the ketogenic diet requires you to cut out carbohydrates until you’re in ketosis.  Your brain and muscles prefer to use carbohydrates as a source of fuel.  When you don’t provide this to your body through your diet, your body has to break down fatty acids and convert them into ketones, the only other source of fuel your brain can use.   This process is called ketosis.1

What You Can Eat: On the ketogenic diet, you can eat as much as you want of foods that don’t provide carbohydrates.  This means seafood, poultry, cheese, avocadoes, eggs, Greek yogurt, and oils are encouraged in large quantities.  You can also still eat small amounts of carbohydrate-containing foods and remain in ketosis.

What You Can’t Eat: The exact amount of carbohydrates you can eat and remain in ketosis varies from one person to the next, but in general people on the ketogenic diet usually eat less than 50 grams of carbohydrates per day.1 To put it into perspective, there are about 15 grams of carbohydrates in a slice of bread, 12 grams of carbohydrates in 1 cup of skim milk, and 27 grams of carbohydrates in a medium banana.

It’s also important to remember that high-protein diets may push you out of ketosis, because some proteins can be converted into glucose.1

What the Research Says: Over the short term, ketogenic diets have been shown to result in weight loss more quickly than traditional diets.  After about 6 months, the weight loss levels out, and ketogenic diets are not shown to be any more effective than traditional diets for long-term weight loss.  At the same time, this restrictive, high-fat diet can increase your risk for nutrient deficiencies and high cholesterol.1

If you’re an athlete, the ketogenic diet has been shown to limit anaerobic exercise performance.  In one study, athletes experienced decreased exercise performance after following a low-carbohydrate diet for only four days.2

The Verdict: There is not enough evidence that the ketogenic diet has any long-term health benefits for the average person.  It restricts entire food groups that are important sources of essential nutrients and is likely difficult to follow in the long-term.  At the same time, you still need to think about your overall calorie intake if you want to lose weight.  High-fat foods also tend to be high in calories, and it is your overall calorie intake that will promote weight loss, not just the amount of carbohydrates you eat.

The Paleo Diet

The Paleo diet encourages you to adopt the eating habits of your Paleolithic ancestors from about 2 million years ago.

One major flaw of this diet is that people don’t know exactly what foods were available to humans 2 million years ago.  The foods eaten at that time would have depended on where in the world those humans were living.  It is also very difficult to say that the foods available in our grocery stores today are the same as they would have been in prehistoric times.

What You Can Eat: In general, the Paleo diet allows you to eat meat, fish, shellfish, eggs, nuts, seeds, fruits, vegetables, olive oil, coconut oil, and some honey.3 You are encouraged to eat unprocessed foods in their natural state.

What You Can’t Eat: As people in the Paleolithic times were hunters and gatherers, the Paleo diet discourages you from eating anything that would not grow wild on its own.  This means avoiding both whole and refined grains, sugar, dairy products, beans, peanuts, lentils, alcohol, coffee, and refined vegetable oils.3

What the Research Says: Many of the studies that examine the Paleo diet are short-term and involve fewer than 40 participants.  Despite this, they indicate that the Paleo diet may result in more positive health changes than the control diets.  In general, people who followed the Paleo diet tended to lose more weight and improve their blood pressure, insulin sensitivity, and cholesterols more significantly.3,4

The Verdict:  The Paleo diet’s recommendations to choose unprocessed foods and encouragement of lean protein, fruits, vegetables, nuts, and seeds are all health-supportive.  However, there need to be some long-term, larger-scale studies that evaluate its effectiveness before any conclusions can be drawn about the Paleo diet being better than a general balanced meal pattern.  Furthermore, unless you are allergic to grains, dairy, beans, peanuts, or lentils, there is absolutely no reason to avoid them entirely.  These foods provide a variety of nutrients that are essential for your health, including fiber, protein, B vitamins, calcium, and potassium.  Furthermore, people who eat these foods are at a lower risk for many different diseases, including heart disease and diabetes.

The Alkaline Diet

Proponents of the Alkaline diet claim that you need to eat foods that will not make your body become overly acidic, as an acidic environment can promote cancer development.  They claim that you can prevent your body from becoming acidic by choosing foods whose breakdown products are alkaline, or have a pH above 7.5

What You Can Eat: Fruits, vegetables, legumes, and nuts are considered alkaline foods (their breakdown products will increase your body’s pH), and fats, starches, and sugar are considered neutral (they have no impact on your body’s pH).

What You Can’t Eat: Meat, poultry, fish, dairy, eggs, grains, alcohol, coffee, soda, and other stimulants are considered acidic, and the Alkaline diet advises you to avoid them.5,6

What the Research Says: When the US News and World Report reviewed the Alkaline diet, they indicated that it may have a positive impact on weight loss or maintenance, reduced risk of diabetes, and improved heart health.  However, any health improvements seen while following the Alkaline diet are more likely caused by reducing your intake of processed foods and choosing more fruits, vegetables, and plant-based protein.6

The rationale behind the Alkaline diet is based on a fundamental misunderstanding of how the human body works.  Your body regulates your blood pH level within the small range of 7.36-7.44; if you are otherwise healthy, your blood pH stays within this range regardless of what you eat because moving outside of this range can lead to organ dysfunction or death.  You may excrete more or less acid in your urine in order to keep blood pH at a safe level, but the pH of your urine is not solely determined by the acidity or alkalinity of your diet.5

The Verdict: You can improve your health and may experience some weight loss by choosing a diet high in fruits, vegetables, and plant-based protein, and limiting your intake of processed foods, sugar, and alcohol.  These health improvements will not be related to changing your body’s pH.  At the same time, acidic foods like meat, poultry, fish, eggs, and whole grains are also health promoting, and absolutely fit into a balanced meal pattern.

Intermittent Fasting

In short, Intermittent Fasting involves setting specific times when you will and will not eat.  These time limits can occur within a day or within a week.  Some people give themselves 8-hour windows to eat every day (10 am – 6 pm), limit themselves to 500-700 calories every other day, or even go as far as spending two days each week fasting completely.7

What You Can Eat: With Intermittent Fasting, you are able to eat whatever you’d like within the time limits you set yourself.

What You Can’t Eat: Intermittent Fasting only restricts you from eating at specific times during the day or week.

What the Research Says: Many of the studies on Intermittent Fasting are short-term (lasting between 2 and 6 months).  This research indicates that the diet can be safe for the average person, does not lead to “compensatory overeating” during the days or times when you are allowed to eat, and can contribute to decreased insulin resistance.7–9 That being said, people who practiced Intermittent Fasting did not lose significantly more weight than people who took a more traditional approach to weight loss and limit what they eat overall.9,10

At the same time, Intermittent Fasting may also be associated with guilt, social isolation, irritability, obsession with food, and lethargy, all of which mimic the signs of an eating disorder.  Although fasting alone hasn’t been shown to directly cause eating disorders, it could definitely trigger a relapse in someone who has recovered from an eating disorder, and does not promote a positive, healthy relationship with food.

The Verdict: If weight loss is your goal, you may find it helpful to limit yourself to eating at certain times of the day.  For example, some people like to consider the kitchen “closed” after 8 pm.  More extreme versions of fasting are not likely to result in better outcomes than simply limiting what you are eating overall.

If It Fits Your Macros (IIFYM)

If you tend to be numbers-focused, you may be interested in the Macro Diet.  This diet goes beyond calorie counting by encouraging people to track their carbohydrate, protein, and fat intake every day to make sure they’re sticking to a goal.  To be successful with this diet, you’d have to carefully track the calorie and macronutrient content of everything you eat, either with a smartphone app or by looking up nutrition fact information and logging that by hand.11,12

What You Can Eat

You can eat anything you want on this diet – as long as it fits within your macronutrient allowance!  If you aren’t working with a Registered Dietitian, the diet explains how to calculate this yourself.  First, use an online calculator to estimate your resting metabolic rate, or the number of calories you need to eat in a day to keep your body functioning without accounting for physical activity.  The calculator will help you determine your final calorie needs depending on your activity level and weight goal.

To find your macronutrient goals, first calculate protein using the recommended 0.7-1.0 grams per pound of your body weight.  Your fat goal will be within 0.25-0.4 grams per pound of body weight.  Whatever calories you have remaining will be for carbohydrates.12

What You Can’t Eat

This diet doesn’t advise people to stay away from any specific foods, as long as they are eating within their macronutrient goals.

What the Research Says

Critics of this diet point out that it doesn’t address diet quality.  For example, it could be possible for someone to stay within their calorie and macronutrient goals every day without eating any fruits, vegetables, or whole grains, and therefore become nutrient-deficient or remain at an increased risk of disease.11 At the same time, studies have shown that calorie-counting apps don’t provide enough support to help their users create lasting healthy habits.13 Instead, users may lose weight as they become more aware of their overall calorie intake and choose smaller portions of high-calorie foods, but will likely return to their previous eating habits when they stop tracking their diets.

At the same time, calorie counting is not effective, or even safe, for everyone.  You can find many personal accounts of people who developed an eating disorder after starting to track their calorie intake by worsening the rigid, numbers-focused thinking often seen in disordered eating.  One study that assessed disordered eating behaviors in college students found that those who tracked their calorie intakes were more likely to engage in disordered eating behaviors.14 It is also commonly known that calorie counting can trigger a relapse in someone who has recovered from an eating disorder, as it often leads to more preoccupation with food choices and the perception that higher-calorie foods must be limited.

The Verdict

While it is often helpful to be aware of your calorie and macronutrient intake, if you set goals without considering the overall quality of your diet you put yourself at risk for vitamin and mineral deficiencies.  At the same time, logging every food, every day, may lead to unhealthy preoccupation with your calorie intake that could turn into disordered eating.  If you are curious about your calorie and macronutrient goals, work with a Registered Dietitian who will help you set realistic goals and learn how to turn them into long-term behavior change, so you will feel confident that you’re eating to promote health without needing an external guide for the long term.

The Mediterranean Diet

Consistently rated the best diet for overall health, the Mediterranean diet was also rated the easiest diet to follow in 2019 by US News and World Report.  In addition to emphasizing meals rich in fruits, vegetables, whole grains, and lean protein, the Mediterranean diet also encourages you to get active regularly and to slow down and savor your meals.15,16

What You Can Eat: This diet encourages you to make fruits and vegetables the basis of your meals.  In addition, you can have olive oil and whole grains every day, and, if you’d like, a 3-5 ounce serving of red wine every night.  Legumes, nuts, fatty fish, whole grains, lean meat, eggs, low-fat dairy products are also encouraged, but limited to three servings per week each.17

What You Can’t Eat: The Mediterranean diet encourages you to avoid added sugars, saturated fats like butter or coconut oil, fried foods, and refined grains.  You may have dessert once per week.

What the Research Says: Many large-scale, long-term studies support the health benefits of the Mediterranean diet.  This diet is associated with a lower risk of heart disease, high cholesterol, and diabetes.  In addition, some research suggests the Mediterranean diet may reduce your risk for Alzheimer’s disease.15

The Verdict: If you are looking for a diet to follow in 2019, the Mediterranean diet is the one.  It has been consistently rated one of the healthiest and easiest to follow diets since it gained popularity, and it is supported by a wide base of well-designed research studies.  Furthermore, this diet is flexible, allows for customization according to your lifestyle and food preferences, and includes meals that will keep you full and satisfied.15

There are pros and cons to any diet, and there is no one meal pattern that will work exactly the same for every person.  When it comes to selecting the one that’s right for you, consider how sustainable it will be, whether it will fit into your lifestyle, and whether it allows foods that you enjoy.  Most importantly, make sure you are eating a variety of foods from each food group, choosing meals that keep you full and satisfied, and creating a lifestyle that will allow you to maintain your health well into the future.


  1.  Sumithran P, Proietto J. Ketogenic diets for weight loss: A review of their principles, safety and efficacy. Obes Res Clin Pract. 2008;2(1):1-13. doi:10.1016/j.orcp.2007.11.003
  2.  Weiss E, Wroble K, Trott M, Schweitzer G, Rahman R, Kelly P. Low-carbohydrate, Ketogenic Diet Impairs Anaerobic Exercise Performance. J Acad Nutr Diet. 2018;118(9):A46. doi:10.1016/j.jand.2018.06.176
  3.  Boston 677 Huntington Avenue, Ma 02115 +1495‑1000. Diet Review: Paleo Diet for Weight Loss. The Nutrition Source. https://www.hsph.harvard.edu/nutritionsource/healthy-weight/diet-reviews/paleo-diet/. Published July 24, 2018. Accessed January 14, 2019.
  4.  5 Studies on The Paleo Diet – Does it Actually Work? https://www.healthline.com/nutrition/5-studies-on-the-paleo-diet. Accessed January 14, 2019.
  5.  The Alkaline Diet: An Evidence-Based Review. Healthline. https://www.healthline.com/nutrition/the-alkaline-diet-myth. Published October 2, 2018. Accessed January 14, 2019.
  6.  Alkaline Diet: What To Know | US News Best Diets. https://health.usnews.com/best-diet/acid-alkaline-diet. Accessed January 14, 2019.
  7.  Mattson MP, Longo VD, Harvie M. Impact of intermittent fasting on health and disease processes. Ageing Res Rev. 2017;39:46-58. doi:10.1016/j.arr.2016.10.005
  8.  MPH MT MD. Intermittent fasting: Surprising update. Harvard Health Blog. https://www.health.harvard.edu/blog/intermittent-fasting-surprising-update-2018062914156. Published June 29, 2018. Accessed January 14, 2019.
  9.  Collier R. Intermittent fasting: the science of going without. CMAJ Can Med Assoc J. 2013;185(9):E363-E364. doi:10.1503/cmaj.109-4451
  10.  The Fast Diet: A Fast Route to Disordered Eating? Psychology Today. http://www.psychologytoday.com/blog/hunger-artist/201411/the-fast-diet-fast-route-disordered-eating. Accessed January 14, 2019.
  11.  The macros diet takes calorie counting to the next level: Does it really work? Washington Post. https://www.washingtonpost.com/lifestyle/wellness/the-macros-diet-does-it-really-work/2016/06/07/d38a5434-2bf6-11e6-9b37-42985f6a265c_story.html. Accessed January 28, 2019.
  12.  IIFYM (If It Fits Your Macros): A Beginner’s Guide. https://www.healthline.com/nutrition/iifym-guide. Accessed January 28, 2019.
  13.  Davis SF, Ellsworth MA, Payne HE, Hall SM, West JH, Nordhagen AL. Health Behavior Theory in Popular Calorie Counting Apps: A Content Analysis. JMIR MHealth UHealth. 2016;4(1). doi:10.2196/mhealth.4177
  14.  Simpson CC, Mazzeo SE. Calorie counting and fitness tracking technology: Associations with eating disorder symptomatology. Eat Behav. 2017;26:89-92. doi:10.1016/j.eatbeh.2017.02.002
  15.  Mediterranean Diet: What It Is & What to Know. https://health.usnews.com/best-diet/mediterranean-diet. Accessed January 14, 2019.
  16.  Mediterranean Diet | Oldways. https://oldwayspt.org/traditional-diets/mediterranean-diet. Accessed January 14, 2019.
  17.  How You Can Get Started on the Mediterranean Diet. Health Essentials from Cleveland Clinic. https://health.clevelandclinic.org/can-get-started-mediterranean-diet/. Published October 15, 2015. Accessed January 14, 2019.

Protein Needs Change with Age

Submitted by Amy Sercel MS RD CD

Edited by Marcia Bristow MS RDN CSSD CD

Starting at age 50, your muscle mass begins to decrease each year.  This age-related muscle loss is called sarcopenia.  It’s normal and it happens to everyone to some degree.  However, extreme loss of muscle mass can lead to frailty, fatigue, falls, fatigue, and even insulin resistance, all of which can result in a loss of independence for the older adult.1 Because of this, maintaining muscle mass is crucial for promoting health and longevity as you age.  One of the most important factors in slowing the rate of muscle loss is consuming enough protein on a day to day basis.2,3

Dietitians used to believe that adults over the age of 18 only needed 0.8 grams of protein per kilogram of their body weight each day.  Recent research, however, suggests that adults over the age of 65 actually need between 1 and 1.3 grams of protein per kilogram of their body weight to support muscle maintenance.  In fact, one study found that adults’ muscle mass still decreased when they were meeting the general recommendation by eating 0.8 g protein per kilogram of their weight every day.3 In more practical terms, this means, once they reach the age of 65 …

  • An adult weighing 130 lb would need 60-76 g protein per day
  • An adult weighing 150 lb would need 68-88 g protein per day
  • An adult weighing 170 lb would need 77-100 g protein per day
  • An adult weighing 200 lb would need 90-118 g protein per day

In addition to getting enough protein on a daily basis, it is also important to be aware of the quality of protein you eat.  All protein molecules are made up of amino acids that link together and determine the protein’s final structure.  There are nine amino acids that your body can’t make, and have to be provided by the food you eat; these are considered essential amino acids.  The other amino acids are considered non-essential, and can be produced in your body.  High-quality sources of protein provide all of the essential amino acids, and some studies show that people don’t need to eat as much protein each day if all of their protein comes from high-quality sources.3

Animal products, such as meat, fish, eggs, and dairy products, provide all of the essential amino acids.  A few plant products, such as soy, quinoa, hemp seeds, buckwheat, and pumpkin seeds, also contain all of the essential amino acids.  You can also combine sources of whole grains with legumes or nuts to create meals that provide all of the essential amino acids.  People used to believe it was necessary to combine these foods within the same meal to absorb all of the amino acids.  Dietitians now know that this isn’t true, and as long as you eat a mix of these foods throughout the day you will meet your essential amino acid requirement.

Studies also suggest that spreading protein intake throughout the day will be most effective for preventing muscle breakdown and maintaining muscle mass. It appears that the ideal protein distribution is about 30 grams of protein at each meal; studies have shown that there is no additional increase in muscle growth when people eat much more than 30 grams of protein at once.2–4 This means that many adults need to increase the amount of protein they eat at breakfast and lunch, and decrease the amount they eat at dinner.  For example, a day that includes 30 grams of protein per meal would be:

  • Breakfast sandwich with 2 scrambled eggs, 1 oz Cheddar cheese, spinach, and tomato on 2 slices whole grain bread, with an 8-oz glass of milk on the side
  • Lunch: green salad with 2 cups vegetables, 3 oz tuna canned in water, 1 cup canned white beans, and a 6-inch whole grain pita on the side
  • Dinner: stir fry with 1 cup cooked quinoa, ½ cup cooked lentils, 2 oz grilled chicken, and 1 cup mixed vegetables

Lastly, engaging in strength training exercise at least twice per week will also help you maintain a high muscle mass.3 If you aren’t already doing regular resistance exercise, start slowly and work your way up as you build your strength, and consider working with a trainer who will make sure you’re doing the exercises correctly.  This regular activity is crucial for stimulating your body to increase your muscle mass.

If you’re concerned that you aren’t eating enough protein each day or would like support to make sure you’re distributing your protein evenly throughout the day, make an appointment with a Registered Dietitian who can determine your unique protein needs and help you create a plan that will fit with your lifestyle.  An ideal plan will allow you to maintain your muscle mass, strength and independence as you get older.


  1.  Walston JD. Sarcopenia in older adults. Curr Opin Rheumatol. 2012;24(6):623-627. doi:10.1097/BOR.0b013e328358d59b
  2.  Nowson C, O’Connell S. Protein Requirements and Recommendations for Older People: A Review. Nutrients. 2015;7(8):6874-6899. doi:10.3390/nu7085311
  3.  Baum JI, Kim I-Y, Wolfe RR. Protein Consumption and the Elderly: What Is the Optimal Level of Intake? Nutrients. 2016;8(6). doi:10.3390/nu8060359
  4.  Protein for Fitness: Age Demands Greater Protein Needs. https://www.todaysdietitian.com/newarchives/040715p16.shtml. Accessed October 1, 2018.

A Diet Customized to Your DNA

Submitted by Amy Sercel MS RD CD

Edited by Marcia Bristow MS RDN CSSD CD

It seems like it couldn’t get any better: a nutrition plan truly tailored just for you, created using your genetic blueprint.  Is this the answer to fad dieting, weight cycling and frustration?  Unfortunately, it appears that the science just isn’t quite there yet, and the promises from “DNA diet” companies might be too good to be true.

The premise behind the DNA diet makes sense.  Your genes hold information about your chance of getting certain diseases, such as obesity, diabetes, or high cholesterol.1 You can influence whether or not your body expresses certain genes by becoming more physically active or making different food choices.  There are even genetic markers that suggest whether you may be better able to metabolize fat or carbohydrates,2 which in theory would determine whether you should eat a high-fat or high-carbohydrate diet.

A recent study called DIETFITS examined this theory by placing 600 participants on either a high-fat or high-carbohydrate diet.  The participants got regular instruction about weight loss strategies while following their assigned diet.  During the course of the study, the researchers categorized participants as “low-fat genotype,” “low-carbohydrate genotype,” or “sensitive to neither genotype” depending on whether their DNA contained any of three different variations. After one year, participants on the high-fat diet had lost about the same amount of weight as the people on the high-carbohydrate diet, regardless of their genotype, and whether they followed the diet that “matched” their genetic sensitivity to fat or carbohydrates.2

The DIETFITS study also gave participants a glucose tolerance test to see whether their insulin sensitivity was related to their success with weight loss on a low-carbohydrate vs. low-fat diet.  Researchers believed that people who were insulin resistant would do better on a low-carbohydrate diet.  After one year, however, researchers found that glucose tolerance had no impact on weight loss for people in either the low-carbohydrate or low-fat group.2

Part of the reason it’s so difficult to accurately match a person’s genes to their ideal diet is that many different genes are associated with weight, and your environment and behaviors influence how these genes will be expressed.1 For example, a high activity level is associated with a stronger immune system, possibly because being active triggers small amounts of inflammation, and as a result the body makes more copies of the proteins needed to fight inflammation.3 In order to say for sure whether DNA diets are truly the thing of the future, there will have to be more, well-designed research studies that evaluate the expression of more than just three genes, and follow participants for longer than just one year.  This way, researchers will be able to say whether the diets support both weight loss and weight maintenance over time.

In the meantime, if you’re still curious about the DNA diet, there are many companies that can perform this service for you.  The cost ranges from about $50 to $200, depending on the depth of information and amount of support you receive.  Most of the tests ask you to send in a saliva sample so they can map your DNA.  Some also measure your insulin sensitivity and other markers of disease risk like cholesterol and triglycerides to help you create a meal plan that will maximize your overall health in addition to promoting weight loss.  For example, if a test measures your insulin sensitivity, they send a glucose tolerance test, in which you would drink a high-carbohydrate beverage, wait about 30 minutes, prick your finger and collect a blood sample to send back and be analyzed.  If your cells are sensitive to insulin, you will have less glucose remaining your blood.  If you are insulin resistant, your blood sugar may be higher.  Insulin resistance is a precursor to diabetes, so if you have a family history or other risk factors for this disease, you’ve probably had a glucose tolerance test at a doctor’s visit.

These companies’ websites do not include many specific details of how the test results inform their recommendations (they’re probably trade secrets!).  Most likely, if someone’s test indicates they’re insulin resistant, they will be given a low-carbohydrate meal plan to help reduce their chances of getting diabetes.  Along the same lines, if someone’s blood test suggests they have high triglycerides, that person will likely be given a low-fat meal plan.  These findings would be used in combination with the results of the saliva sample DNA test.  Marcia is ordering a test kit to learn more about the process and will be able to provide more information about this in the near future.

It’s important to note that even without a personalized DNA diet plan, you can still make healthy diet and lifestyle choices that will impact your overall health and reduce your risk of disease.  In one study, men with low-risk prostate cancer adopted a low-fat diet, increased their activity level to be active for about 4 hours per week, and spent time prioritizing stress reduction.  After 3 months, genetic evaluation showed that they were producing fewer of the genes associated with tumor development.1 In the DIETFITS study, all of the participants were told to eat more vegetables, eat less added sugar and refined grains, and focus on whole, unprocessed foods whenever possible.2 You will likely see similar health benefits and reduce your risk of disease by practicing stress reduction, getting active, eating more fruits and vegetables, and eating fewer refined grains.  For support with this, contact a Registered Dietitian who will give you evidence-based recommendations that work with your lifestyle to reduce your risk of disease over the long-term and reach any other nutrition-related goals you might have.


  1.  Camp KM, Trujillo E. Position of the Academy of Nutrition and Dietetics: Nutritional Genomics. J Acad Nutr Diet. 2014;114(2):299-312. doi:10.1016/j.jand.2013.12.001
  2.  Gardner CD, Trepanowski JF, Gobbo LCD, et al. Effect of Low-Fat vs Low-Carbohydrate Diet on 12-Month Weight Loss in Overweight Adults and the Association With Genotype Pattern or Insulin Secretion: The DIETFITS Randomized Clinical Trial. JAMA. 2018;319(7):667-679. doi:10.1001/jama.2018.0245
  3.  Gjevestad GO, Holven KB, Ulven SM. Effects of Exercise on Gene Expression of Inflammatory Markers in Human Peripheral Blood Cells: A Systematic Review. Curr Cardiovasc Risk Rep. 2015;9(7). doi:10.1007/s12170-015-0463-4

What’s the Best Supplement for Muscle Building?

Submitted by Amy Sercel MS RD CD

Edited by Marcia Bristow MS RDN CSSD CD

If you have a goal of maintaining or building up your muscle mass, you’re probably familiar with the many protein supplements on the market.  It seems like they all claim to be the most effective one around!  While many athletes don’t need protein supplements because they get enough protein from food and beverages,1 supplements can be helpful if you’re having trouble meeting your protein needs.  They can be especially valuable if you follow a low- or no-meat diet or if you have a lower appetite.  Since they’re portable and easy to prepare, supplements can also be more convenient, and using one may also give you the peace of mind to know that you’re meeting your protein needs every day.

When it comes to protein, there are many different supplements you can use.  Two popular types are whey and casein powders, which both come from milk.  A third type, collagen powder, has become popular more recently and is made from fish or beef.2

Many studies conclude that whey is more effective than casein for promoting muscle growth.3,4 Both contain all of the essential amino acids.  Amino acids are the building blocks that link together to make a protein.  An amino acid is considered essential when your body can’t make it, so you have to get it from food.  Whey and casein are different because they contain different amounts of each essential amino acid.  Whey has been shown to increase muscle growth more than casein, possibly because it is digested and absorbed more quickly.  Whey also contains twice as much of the essential amino acid leucine.4,5 Leucine has been shown to stimulate muscle growth when other essential amino acids are also available.  It works by starting the signal to begin muscle building.  In one study, rodents who had lost muscle mass were able to regain about 60% of the muscle that was lost when supplemented with whey protein alone or with whey and casein together, suggesting that the whey was responsible for the increase in muscle mass.6

This is not to say that casein is completely useless!  Because you digest and absorb casein more slowly, researchers have started to investigate the impact of consuming it before bed.  It appears that athletes who ingest 30-40 grams of casein about 30-90 minutes before bed experience increased muscle growth and resting metabolic rate during the night.7 Interestingly, using a casein supplement before bed may not be as effective in people who are more sedentary, or in people who already have a high protein intake.  In one study of 12 obese, sedentary men, consuming 30-40 grams of casein before bed had no impact on resting metabolic rate or muscle growth overnight.8 This suggests that bedtime casein supplements will have the most impact on muscle growth if you are also engaging in regular physical activity.

There are fewer studies available that compare whey and collagen supplements.  Researchers in Ontario, Canada are currently investigating this subject, but they are still in the data collection phase of their research and have not yet published any results.9 The few studies that have been published examine the impact of whey and collagen supplementation on the muscle mass of elderly women in an assisted living facility.  In this population, it appears that collagen supplements promote muscle growth and maintenance better than whey supplements do.  In one study, when the women were supplemented with whey their muscle mass actually decreased slightly.10 When they were given the collagen supplements, the women’s lean body tissue increased and their fat tissue decreased.  While collagen contains a smaller proportion of leucine than whey protein, collagen’s overall amino acid content appears to be more beneficial for maintaining muscle mass than whey.11

In the end, if you’re thinking about a protein supplement to support muscle maintenance or growth, research suggests that whey, casein, and collagen can all be effective.  If you’re trying to choose between the three, keep in mind that whey and casein come from dairy; collagen comes from fish or cows and would not fit into a vegetarian meal pattern.  On the other hand, collagen has been associated with reduced arthritis symptoms in addition to its impact on muscle growth, so it may be helpful to choose this supplement if you also experience joint pain or inflammation.2 Stay tuned for the results of the study coming out of Ontario within the next few years as well, since this will provide a new perspective to inform the research.  If you’d like support with learning how much protein you should eat in a day or finding a supplement that will meet your needs, reach out to a Registered Dietitian who can provide personalized suggestions that will fit your lifestyle.


  1.  Dunford M, Doyle JA. Nutrition for Sport and Exercise. 3rd ed. Cengage Learning; 2015.
  2.  Is Collagen Worth the Hype? | MyFitnessPal. Armour. March 2018. https://blog.myfitnesspal.com/collagen-worth-hype/. Accessed July 27, 2018.
  3.  Eitel J. The Breakdown of Whey Protein Amino Acids. LIVESTRONG.COM. https://www.livestrong.com/article/518213-the-breakdown-of-whey-protein-amino-acids/. Accessed July 27, 2018.
  4.  Whey vs Casein: Which one best maintains muscle mass? – Nutrition Express Articles. Nutrition Express. http://www.nutritionexpress.com:9080/article+index/authors/jeff+s+volek+phd+rd/showarticle.aspx?id=1082. Accessed July 27, 2018.
  5.  Typical amino acid composition of whey, casein, and soy isolates  | Download Table. https://www.researchgate.net/figure/Typical-amino-acid-composition-of-whey-casein-and-soy-isolates_tbl2_227249571. Accessed July 27, 2018.
  6.  Breen L, Churchward-Venne TA. Leucine: a nutrient “trigger” for muscle anabolism, but what more? J Physiol. 2012;590(Pt 9):2065-2066. doi:10.1113/jphysiol.2012.230631
  7.  Kerksick CM, Arent S, Schoenfeld BJ, et al. International society of sports nutrition position stand: nutrient timing. J Int Soc Sports Nutr. 2017;14(1):33. doi:10.1186/s12970-017-0189-4
  8.  Kinsey AW, Cappadona SR, Panton LB, et al. The Effect of Casein Protein Prior to Sleep on Fat Metabolism in Obese Men. Nutrients. 2016;8(8). doi:10.3390/nu8080452
  9.  The Effects of Whey vs. Collagen on MPS – Full Text View – ClinicalTrials.gov. https://clinicaltrials.gov/ct2/show/NCT03281434. Accessed July 27, 2018.
  10.  Hays NP, Kim H, Wells AM, Kajkenova O, Evans WJ. Effects of Whey and Fortified Collagen Hydrolysate Protein Supplements on Nitrogen Balance and Body Composition in Older Women. J Am Diet Assoc. 2009;109(6):1082-1087. doi:10.1016/j.jada.2009.03.003
  11.  Zdzieblik D, Oesser S, Baumstark MW, Gollhofer A, König D. Collagen peptide supplementation in combination with resistance training improves body composition and increases muscle strength in elderly sarcopenic men: a randomised controlled trial. Br J Nutr. 2015;114(8):1237-1245. doi:10.1017/S0007114515002810