Staying on top of the latest sports nutrition information is a challenge. That’s why I attend the annual meeting of the American College of Sports Medicine (ACSM). ACSM is a professional organization for sports medicine doctors and health-care providers, sport dietitians, exercise physiologists and sport science researchers. More than 3,000 ACSM members gathered in Minneapolis (May 2018) to share their knowledge and latest research. The following summarizes a Sports Nutrition Update session presented by many leading exercise scientists from around the globe.

Fat vs. Carb

Gareth Wallis PhD, Univ. Birmingham, UK

Which will better enhance athletic performance: A high carbohydrate or a high fat sports diet? Despite growing interest in a high fat sports diet, research does not support it for athletes who exercise at high intensity. Rather, research supports consuming 3 to 4.5 grams carbohydrate per pound  (7-10 g carb/kg) body weight per day to be well fueled for hard training and competitive events.

Grains, fruits and veggies are obligatory if you want to exercise hard. Some athletes eat a high fat diet for training and then switch to carb-loading before a competitive event. Bad idea. The enzymes involved in metabolizing carbohydrate become less active, so the muscles are less able to access carbs for fuel when it is needed for winning sprints and surges.

Protein for Athletes

Nicholas Burd PhD, Univ Illinois and Trent Stellingwerff  PhD. Canadian Sport Institute

If you want to build muscle, when is the best time to eat protein: before, during or after you lift weights? It might not actually matter because resistance exercise stimulates a muscle-building effect that is most robust within the first 4 hours but lasts for 1 to 2 days. You need not carry a protein shake around the gym! More important is to pace your protein intake evenly throughout the day.

Resistance exercise is far more potent than a high protein diet for increasing strength and muscle gains. That said, most athletes could expect to see only a gain of about 2 pounds (1 kg) of muscle in 13 weeks. That’s not very much compared to what they really want to see.

Maximal anabolic (muscle-building) effects are seen with about 25 to 30 g protein per meal. More precisely: 0.75 g protein per pound of body weight per day, or 0.1 to 0.2 g protein per pound per meal in young men. More than that has little or no further benefit. However, these recommendations do change with age. If you are >50 years old, you should target an additional 10 grams of high quality protein (milk, egg, fish, soy) per meal. That’s just a little bit more: a glass of milk or 1.5 ounces of meat-fish-chicken.

Despite rumors, protein does not damage the kidneys nor cause a decline in kidney function. Even people with chronic kidney disease should consume the RDA for protein (0.8 g/kg). A high protein diet also does not cause bone loss. Bone is 40% to 50% protein (collagen).

Over-consuming protein is not only a waste of money but it also stresses the environment. As athletes, we need to take a holistic and whole-foods approach to our diets. Natural protein-rich foods, as opposed to processed supplements, are best (if compatible with your training schedule) because they offer a complex and complete matrix that is more effective than processed proteins. One example of the benefits of whole foods can be seen with eggs. A whole egg promotes 40% greater muscle protein synthesis in the 5 hours post-exercise as compared to eating just the egg white (van Vliet AJCN 2017). Nutrient interactions seem to facilitate a more robust response when compared to eating isolated protein.

Sport Supplements

Eric Rawson PhD RD, Messiah College

There is no one single sport supplement that works for all athletes. To better understand why, we need a more specific scientific approach to studying supplements based on age, sex, body size, training status, and genetics. That would help us give better advice to target groups of athletes, rather than simply make population-wide recommendations. Many athletes take multiple supplements, so research with “stacked” supplements would also be helpful. Here’s some of what we do know:

Creatine enables an athlete to lift harder in the training room—and build more muscle. But not everyone is a responder. For example, 3 of 11 subjects in a research study had a strong positive response, 5 had a slight response—and 3 did not respond at all (Syrotuik, Bell 2004). Why not? Maybe their daily diets impacted their baseline creatine levels?

Creatine is found in meat and other animal proteins.  When a meat-eating athlete goes on a meat-free lacto-ovo-vegetarian diet (milk, eggs, beans) for 26 days, his or her creatine levels will drop. (Lukaszuk, 2005). To normalize the level, athletes could take creatine monohydrate supplements (the most effective form of creatine).

Caffeine is a known energy-enhancing sport supplement. Your response to caffeine will depend on your genetics. Caffeine works best when you are starting to fatigue. Athletes can consume it in coffee, tea, soda, gels, gum, and pills, preferably consumed with carbs.

Sodium bicarbonate is used by some athletes to buffer the lactic acid that builds up during intense bursts of exercise. Research suggests peak response times can vary widely, from 40-165 minutes. (Jones 2016 ISSN). This variability makes it hard for exercise scientists to offer firm recommendations; hence, outcomes vary. Sub-elite athletes seem to respond better then elite athletes. Because sodium bicarbonate easily causes nausea and vomiting, a solution it to take it in gastro-resistant capsules.

Fluids and Hydration

Linsday Baker, R&D Principal Scientist, Gatorade Sports Science Institute, Pepsi Co.

When you sweat, you lose proportionately more water than sodium, hence sodium levels in the blood increase with dehydration. The amount of sodium you lose in sweat varies from a lot to a little, related to both sweating rate and how well you are acclimated to exercising in the heat, among other factors. A high concentration of sodium in your blood stimulates thirst.

Thirsty athletes have three ways they deal with replacing fluid losses: hit-or-miss ad lib drinking as desired; drinking to quench thirst; and drinking on a set schedule. The effectiveness of these strategies depends on the individual athletes, availability of fluids, the weather, and exercise intensity and duration. If you happen to have a lot of tattoos, take note: tattooed skin may sweat less and excrete saltier sweat.

Nancy Clark, MS, RD counsels both casual and competitive athletes at her office in Newton, MA (617-795-1875). Her best selling Sports Nutrition Guidebook and food guides for marathoners, cyclists and soccer players offer additional information. They are available at www.NancyClarkRD.com. For her popular online workshop, see www.NutritionSportsExerciseCEUs.com.

Anything that promises detoxification sounds a little questionable – like products that claim to “pull toxins out of your system” or “cleanse the liver.”  The body does have detoxification mechanisms that are working all the time, and both healthful eating and intermittent fasting can accelerate those processes. Several-day juice “fasts” are one way to tap into the benefits of intermittent fasting and enhance removal of toxins from the body, because the body enhances the removal of toxins when not digesting food and burning more fat for its energy needs. Our fat supply stores toxins, and when we lose body fat we release more toxic waste simultaneously. The body also needs adequate phytochemical and antioxidants for the liver to most effectively process fat-soluble toxins so they can be excreted via the urine.

Get into the catabolic phase

We’re always either in a fed state or a fasting state; you’ve likely read about the anabolic and catabolic phases of digestion in my books or articles that discuss toxic hunger. When we are eating, digesting, and absorbing nutrients from food, we are in the anabolic phase; think of it like filling your car’s tank with gas. That is followed by the catabolic phase, between meals, in which our energy needs are met by burning energy that we stored during the anabolic phase.

The catabolic phase is when most healing and self-repair happens, and there is evidence that prolonged time in this fasting (catabolic) state has significant health benefits. Also, these benefits don’t necessarily require an extended, several-day water fast, which is difficult for most people to commit to.

I always say, the longer you live in the catabolic phase, the longer you live. Here’s why: Being in a fasting state shifts the body’s cells away from growth, and instead toward a mode of maintenance and repair.^1,2 This repair mode is associated with a reduction in insulin and insulin-like growth factor-1 (IGF-1) production; two hormones that play a huge role in health and longevity.^3,4 These hormonal changes lead to reduced inflammation, improved insulin sensitivity and stress resistance, slower cell growth, improved immune function, and reduced oxidative stress.^5,6  Fasting also stimulates autophagy, an important self-repair process. Autophagy removes damaged components from cells and tissues.⁷

Eating right is already detox; calorie restriction enhances the benefits

On a cellular level, many dietary phytochemicals – such as isothiocyanates derived from cruciferous vegetables, sulfur compounds from garlic and onions, and carotenoids from a variety of colorful produce – drive the production of enzymes that enable the excretion of carcinogens and other potentially harmful compounds. This detoxification system counteracts oxidative stress, inflammation, and DNA damage.⁸  Eating right, in itself, enables valuable detoxification mechanisms.

Caloric restriction adds to this, and has been the one intervention that extends life in a number of different species. Adding periodic calorie restriction to an already nutrient-rich diet could intensify the body’s ability to heal and repair by extending the amount of time in the fasting repair mode and reducing growth-related signals.⁴  It also can enhance the breakdown and excretion of fat-soluble toxins; lowering the body’s toxic load.

Intermittent fasting

Intermittent fasting or a juice detox could also be a warm-up to incorporating occasional water fasting. Back in 1995, in my book, Fasting and Eating For Health, I discussed my experience of how fasting improved health parameters in my patients. I also co-authored a series of case reports documenting remission of autoimmune diseases following supervised fasting.⁹  More recently, fasting has been shown to have dramatic regenerative effects on the immune system. Studies over the past few years in animals and humans have suggested that fasting signals the immune system to discard old and damaged cells and generate new cells by increasing hematopoietic stem cells. The reduction in IGF-1 signaling was a necessary factor in this immune boosting. ^6,10

Intermittent fasting – usually by reducing calorie intake dramatically a few days per week – is a method for getting some of the benefits of longer-term fasting. Human studies on intermittent fasting suggest it improves insulin sensitivity and promotes weight loss.^2,11,12

I recommend incorporating a juice detox into your life, with vegetable juices plus one salad per day for several days, to act as a method of intermittent fasting, to slow aging and prolong lifespan as an easier alternative to water fasting.  Water fasting has a rapidly decreasing effect at removing toxins, as nutrients necessary for the removal also decrease as the fast progresses. Also, juice fasting enables the participants to continue to work and is safer, compared to water fasting, as it prevents dehydration, loss of electrolytes and fainting. It is also compatible for people who must remain on medications, so almost anyone can participate.

Tips for juicing wisely

• Figure out a timeline you’re comfortable with. You may want to try juicing one day a week, or you may want to try a week-long juice cleanse.
• Juice should be mostly vegetables, not fruit. Apple juice with a little kale added doesn’t bring much benefit. The maximum amount of fruit in a vegetable juice should be one serving of a low-sugar fruit, such as green apple or berries. The rest should be nutrient-rich vegetables, leafy greens in particular. Lemon and lime juice can be added to flavor your juice without counting toward the fruit serving. Include cucumber, lettuce and celery juice, along with carrots, beets, and some leafy cruciferous greens such as cabbage, kale or bok choy.
• Follow it up with a health-promoting diet. A few days of juicing can be a great way to reset your taste buds and jumpstart a new, healthful, nutrient-rich diet. However, there is no health benefit of trying to use a juice cleanse as temporary detox, just a break from an everyday junk food diet. This only works if you stick with a Nutritarian diet for the rest of your life, incorporating some juicing and caloric restriction episodically.
• If you have a serious medical condition or are on any medication, consult a physician before starting a juice detox.

Originally printed on DrFuhrman.com. Reprinted with permission from Dr. Fuhrman.

Dr. Fuhrman is a board-certified family physician specializing in nutritional medicine. He is President of the Nutritional Research Foundation and the author of 6 NY Times bestselling books, including The End of Heart Disease. Visit him at DrFuhrman.com.

References

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2. Mattson MP, Longo VD, Harvie M. Impact of intermittent fasting on health and disease processes. Ageing Res Rev 2017, 39:46-58.
3. Pan H, Finkel T. Key proteins and pathways that regulate lifespan. J Biol Chem 2017, 292:6452-6460.
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5. Longo VD, Mattson MP. Fasting: molecular mechanisms and clinical applications. Cell Metab 2014, 19:181-192.
6. Cheng CW, Adams GB, Perin L, et al. Prolonged Fasting Reduces IGF-1/PKA to Promote Hematopoietic-Stem-Cell-Based Regeneration and Reverse Immunosuppression. Cell Stem Cell 2014, 14:810-823.
7. Mattson MP, Allison DB, Fontana L, et al. Meal frequency and timing in health and disease. Proc Natl Acad Sci U S A 2014, 111:16647-16653.
8. Stefanson AL, Bakovic M. Dietary regulation of Keap1/Nrf2/ARE pathway: focus on plant-derived compounds and trace minerals. Nutrients 2014, 6:3777-3801.
9. Fuhrman J, Sarter B, Calabro DJ. Brief case reports of medically supervised, water-only fasting associated with remission of autoimmune disease. Altern Ther Health Med 2002, 8:112, 110-111.
10. Wu S. Fasting triggers stem cell regeneration of damaged, old immune system. In USC News, 2014 [http://news.usc.edu/63669/fasting-triggers-stem-cell-regeneration-of-damaged-old-immune-system/]
11. Antoni R, Johnston KL, Collins AL, Robertson MD. Effects of intermittent fasting on glucose and lipid metabolism. Proc Nutr Soc 2017, 76:361-368.
12. Tinsley GM, La Bounty PM. Effects of intermittent fasting on body composition and clinical health markers in humans. Nutr Rev 2015, 73:661-67