Strong Nutrition

The worlds fascination with bodybuilding, the process of muscle hypertrophy and fat loss achieved through muscle training and diet, has done nothing but grow over the last few decades. Nutrition has become an important facet in the muscle-building arena. Bodybuilding dietary supplements are so prolific a recent Google search revealed 10.6 million results.

A desire to build lean muscle isnt limited to bodybuilders; it is shared by a variety of athletes. Consumer knowledge of nutritional strategies to build muscle is littered with myths and misperceptions. Athletes frequently rely on dietary regimens and supplements designed to burn fat, increase protein and promote muscle growth.

But are such nutritional strategies proven and effective?

A bodybuilding diet

Dietary regimes for bodybuilders often focus on sufficient calories to cover increased needs for training and increased body muscle mass; protein at levels of 25% to 30% of total caloric intake; and supplements to provide protein, as well as other nutritional compounds that may offer strength benefits.

In 1993, Arizona State University, Tempe, researchers studied a world-class bodybuilders dietary intake during an 8-week pre-competition period (International Journal of Sport Nutrition and Exercise Metabolism, 1993; 3(1):76- 86). He performed two hours of aerobic exercise and three hours of weight training six days per week. The average caloric intake was 4,952 (54 kcal per kg): 76% of calories from carbohydrate, 19% from protein (1.9 grams protein per kg), and 5% from fat. Micronutrient consumption was equal or above 100% of the RDA (except for zinc and calcium) without supplementation. Body fat decreased from 9% to 7% during the period; thus body-weight goals were achieved through a nutrient dense, high-energy and high-carb diet with aerobic and anerobic exercise.

A Dec. 2007 article in the Journal of Sports Sciences (25 Supp. 1:39-47), notes only a handful of studies have been done on nutrition and athletes who require speed, strength and power. Current nutrition recommendations for training and competition include meeting energy needs by timing consumption of adequate fluid and electrolyte intakes before, during and after exercise to promote adequate hydration; timing consumption of carbohydrate to provide adequate fuel for energy demands and of spare protein for muscle repair, growth and maintenance; timing consumption of adequate protein to meet protein synthesis and turnover needs; and consuming effective nutritional and dietary supplements.

Lean, mean supplements

Many nutrients have been hypothesized to enhance strength and muscle mass. The following are approved for food use: whey protein concentrates, beta-alanine, micronutrients (vitamins/minerals), amino acids (i.e., glutamine), astaxanthin and caffeine.

When it comes to protein sources, athletes have debated the value of whey protein over soy protein for its effects on muscle growth. The effects of whey vs. soy protein with resistance training in young adults were examined in a study published in the June 2006 International Journal of Sport Nutrition and Exercise Metabolism (16(3):233-44). It was discovered that protein supplementation during resistance training, independent of source, increased lean tissue mass and strength over isocaloric placebo and resistance training.

Creatine is one of the most-popular for enhancing strength and muscle mass, with over 200 studies performed on its effects. Creatine is an amino acid found naturally in the body, primarily in the skeletal muscle. Some studies show creatine supplements can improve performance in exercises that include short bursts of high-intensity activity with intervening periods of rest, such as weightlifting and sprinting. Creatine can increase muscle size, although most of that is attributed to increased water retention. A 2000 consensus statement by the American College of Sports Medicine, Indianapolis, reported that creatine supplementation exhibits small, but significant, physiological and performance changes, but the performance increases are realized during very specific exercise conditions, suggesting high expectations for performance enhancement are inordinate.

HMB (hydroxymethyl butyrate), a popular strengthenhancing supplement, actually occurs naturally in the body as a metabolite of the amino acid, leucine. Muscle damage during training can break down leucine and increase HMB levels. Some evidence indicates that HMB supplements may trigger the body to slow down muscletissue destruction and improve muscle-growth response in weight training. While a number of studies have supported HMB supplementation in exercise conditions, conflicting results have also been reported. A review of research on the effects of HMB on exercise performance and body composition published online in Nutrition & Metabolism in Jan. 2008 suggested that HMB may inhibit the degradation of intracellular proteins and may also directly stimulate protein synthesis. More research needs to occur to further understand the effectiveness of HMB on strength and muscle mass.

Amino acids are often used by athletes for strength benefits. In particular, glutamine is purported to possess ergogenic effects of increased strength, quicker recovery, decreased frequency of respiratory infections and prevention of the effects of overtraining. Glutamine maintains muscle cells, the immune system and the digestive tract. But, weak evidence supports glutamines benefits for athletes. A review examining the effects of glutamine on exercise published in the July 2007 issue of Current Sports Medicine Reports (6(4):265-8) concluded a lack of evidence exists for definitive positive ergogenic benefits as a result of glutamine supplementation.

Branched-chain amino acids (BCAAs), including leucine, isoleucine and valine, are of interest to athletes to help build muscle, improve performance, delay fatigue and treat overtraining. Muscles are very high in BCAA content, and exercise uses greater amounts of BCAAs than normal activity. But, little evidence links BCAA supplements with their promoted purpose in athletic performance. A researcher from the School of Sport and Exercise Sciences, Loughborough University, Leicestershire, England, reported in the Journal of Nutrition in June 2005 (135(Supp. 6):1591S-5S) that acute intakes of BCAA supplements of about 10 to 30 grams per day seem harmless, but no valid scientific evidence supports commercial claims that orally ingested BCAAs have an anticatabolic effect during and after exercise in humans, or that BCAA supplements may accelerate the repair of muscle damage after exercise.

Many other supplements are promoted as ergogenic aids to provide benefits of speed, strength and endurance. The hot list includes ginseng, medium-chain triglycerides, pyruvate, chromium, coenzyme Q10, policosanol, phosphatidylserine, colostrum and DHA. The scientific research on many such supplements is scant. The National Institutes of Healths Office of Dietary Supplements website (www.dietary-supplements.info.nih.gov) can offer a look at the latest research. According to Rob Skinner, MS, RD, CSSD, CSCS, sports nutrition consultant at University of Virginia Athletics, Charlottesville, Strength training combined with adequate carbohydrates and protein is the only thing guaranteed to increase muscle mass. Everything else is subject to question.

Sharon Palmer is a registered dietitian with 16 years of experience in health-care and foodservice management. She writes on food and nutrition for newspapers, magazines, websites and books. Palmer makes her home in Southern California and can be reached at [email protected].