The Athlete's Kitchen
by Nancy Clark, MS, RD, CSSD
Weight and Protein: Hot Topics at the ACSM Annual Meeting
The American College of Sports Medicine (www.ACSM.org) is the world's largest organization of sports medicine and exercise science professionals. At ACSM's annual meeting in Boston (May, 2016), over 6,800 exercise scientists, sports dietitians, physicians, and health professionals gathered to share their research. Here are a few highlights related to the hot topics of weight management and dietary protein.
Weight management Do we actually know hat drives the obesity epidemic: Is food intake too high? Or does body fatness reduce the desire to exercise? We have much to learn about this delicate balance. Hunger, that irritating feeling that motivates you to eat, is related to muscularity (but not to body fatness). Muscular runners and triathles have more hunger than their less-muscular peers and they need more fuel. Hence, if you love to eat (and be lean), lifting weights could be a helpful addition to your training program! We each have hundreds of types of microbes in our gut that help with digestion. The microbe profile of people with obesity differs from that of lean runners. In mice, we know that obese mice absorb more calories from their food than do their lean counterparts. When the gut microbes of obese mice are transplanted into lean mice, the lean mice start to gain weight. The bottom line: eat a diet that makes for a healthy and slimming gut microbiome: fiber-rich fruits, vegetables, legumes, and whole grain foods. Body fatness is strongly linked to sleep deprivation. In a weight reduction study with 123 overfat adults, those who slept the most lost more weight than those who were sleep deprived. In another study with 77 overfat men, a third of them had undiagnosed sleep apnea. They lost less weight than those who slept well. Clearly, sleep is an essential part of a weight management program. If you sleep poorly and struggle to lose weight, you might want to find out if undiagnosed sleep apnea is part of the problem. Eating the majority of your calories in the earlier part of the day helps to maintain leanness. In a 20-week study with 420 people, the subjects who ate a late lunch lost less weight than those who ate an earlier lunch. Why does meal timing matter if you eat the same amount of calories, only at different times? Diet-induced thermogenesis (the amount of energy needed to digest and assimilate a meal, generally 7% to 10% of calories consumed) is lower at night. Circadian rhythms that drive hunger are also stronger at night compared to morning. Try to frontload your calories? Should athletes in treatment for eating disorders be allowed to exercise? Traditionally, the answer has been no. Current research indicates no adverse effects, as long as the person is medically stable. Yoga, lifting weights, and aerobic exercise (30 minute limit) have been shown to be beneficial in terms of greater muscle mass and weight gain, with fewer disordered eating symptoms. Yes, exercise can be helpful for runners with eating disorders—as long as exercise is moderate and accompanied by adequate fuel.
Protein Protein is a positive addition to a weight management program. One reason, it is satiating (helps keep you feeling fed). Another reason, it helps to curb loss of muscle. (When deprived of fuel, the body breaks down muscles for energy.) The less muscle you have, the fewer calories you burn.Despite popular belief, high protein diets are unlikely to harm your health (if you are healthy). Extra protein does not cause kidney failure, nor does it cause bone loss. Yet, diets high in animal protein can be filled with unhealthy fats, as well as be harmful to the environment. Moderation… Eating extra protein is NOT the key to building muscle. The key is to lift heavier and heavier weights (progressive resistance exercise). Surprisingly, marathoners and body builders have similar protein needs per pound of body weight. Runners should pay attention to not only how much protein they eat but also to when they eat it. Research with 20 grams of protein taken 4 times a day (80 g/day) shows better muscle protein synthesis than 10 grams taken 8 times a day, or 40 grams taken twice a day. Hence runners want to target about 20 grams of protein every 3 to 4 hours at breakfast, lunch, afternoon snack & dinner. Protein needs are based on body weight (not percent of calories). While the total daily need is about 0.5 to 0.75 grams protein per pound (1.2-1.7 g pro/kg), a suggested distribution is 0.12-0.14 grams of protein per pound of body weight per meal (0.25-0.3 g pro/kg). For a 150-pound (68 kg) runner, this comes to about 20 grams protein per meal. For a 120-pound (55 kg) runner, the dose is about 15 g protein/meal. A 200-pound athlete (90 kg) needs about 25 g protein/meal. Most athletes eat more than this; the extra protein does not build bigger muscles. Dieters, serious runners, and masters athletes (who want to reduce muscle loss associated with aging) can benefit from another 40 grams of protein before bed. Extra bedtime protein reduces overnight muscle breakdown and enhances overnight muscle growth. Cottage cheese, anyone? The “anabolic window of opportunity” (optimal time to eat protein after a workout to build muscle) is longer than initially thought. After a weight-lifting session, the muscles are in building-mode for the next two days. In comparison, the best time for refueling depleted muscle glycogen is within the first hour or two after exercise. Your best recovery bet is to enjoy a post-exercise carb-protein combination that both builds and refuels muscles. Eggs and toast? Chicken and rice? Chocolate milk?
Sports nutritionist Nancy Clark MS RD CSSD has a private practice in the Boston-area (Newton; 617-795-1875), where she helps both fitness exercisers and competitive athletes create winning food plans. Her best-selling Sports Nutrition Guidebook, and food guides for marathoners and cyclists, as well as teaching materials, are available at www.nancyclarkrd.com. For online and live workshops, visit www.NutritionSportsExerciseCEUs.com.