Until recently, the specific nutritional needs of bodybuilding competitors were largely ignored by the scientific community. Even worse, when dietary recommendations were provided, they were often similar to those for endurance athletes, despite the significant differences between the two activities. Occasionally, however, a publication does offer bodybuilders some useful nutritional advice. Such was the case with a recent review that examined scientific literature to come up with a specific plan for off-season and precontest bodybuilding diets.1
The researchers looked at the body’s need for the three major energy-producing nutrients, or macronutrients: protein, carbohydrates and fat. Being aware of their correct balance and requirements is vital for promoting optimal gains in muscle mass and losing bodyfat without sacrificing hard-earned muscle.
The authors say the long-held notion of using lighter weights and higher repetitions during precontest preparation is unwarranted and likely to promote a loss of muscle size. Training that way doesn’t burn any additional fat, either. As for spot reducing, or losing fat in specific areas, it just doesn’t exist. When the body burns fat, it does so systemically, not just in one area. It’s more efficient to promote fat loss by restricting calories and increasing aerobic exercise.
Since gaining muscle is an energy-intensive process’that is, it takes additional energy to add lean mass’those seeking added muscle size must increase their total calorie intake. You can’t do it in a haphazard manner, though. The adage, ‘You are what you eat,’ holds true. If your added calories consist mainly of so-called junk foods, such as processed carbohydrates, you’ll wind up with a junk physique, with most of your ‘gains’ consisting of additional bodyfat that you’ll later have to lose.
Muscle is about 22 percent protein and 72 percent water, so the need for protein in building muscle is obvious. Exercise itself promotes increased muscle protein synthesis. One study found that it was elevated by 50 percent four hours following a workout of 12 sets of biceps exercises. By the 24-hour mark muscle protein synthesis had increased to 100 percent over baseline, or resting, rates. Getting sufficient protein after a workout is a critical component in promoting growth.
Exactly how much protein you need is a matter of scientific debate. The suggested protein intake for those not engaged in serious training is 0.8 grams per kilogram of bodyweight daily. Some studies show that for adding muscle, it should be 1.2 to 1.7 grams per kilogram of bodyweight. Other studies show that as you become more advanced in your training, you become more efficient at metabolizing protein. Some scientists suggest that you need no more protein than the average couch potato because you use every bit of it as you become more experienced.
Additional protein in the diet, however, offers benefits beyond muscle anabolism. There is, for example, the thermic effect of protein. Protein requires more calories for assimilation than fat or carbs, so it burns additional calories. It also has a potent appetite-suppressing effect that aids in fat loss and dieting. For those reasons the suggested optimal protein intake should be 25 to 35 percent of total calories.
Glycogen is the storage form of carbohydrate found in muscle and liver and is the major fuel source that powers bodybuilding workouts. One study found that the breakdown of glycogen in muscle, a process called glycolysis, provided 82 percent of ATP for immediate energy needs during a set of biceps curls done to failure.
Eccentric muscle contractions, consisting of lowering the weight during most exercises, lead to extensive muscle damage. The body compensates by increasing muscle protein synthesis and other factors that result in muscular hypertrophy, or growth. On the other hand, the damage to muscle caused by eccentric muscle contractions also interferes with muscle glycogen replenishment, which mandates an increased carb intake and enough rest to allow for recovery.
Based on the need for muscle glycogen to power intense training, the suggested intake for carbs is five to six grams per kilogram daily, or 55 to 60 percent of total energy intake. That recommendation may be more appropriate for the mass-building phases of training, or it could prove excessive for a fat-loss phase.
The importance of dietary fat lies in its relationship to anabolic hormones. Several studies show that a drastic reduction in fat intake leads to a significant decline in testosterone. What’s even more interesting is that some studies show that those who substitute so-called good fats, such as polyunsaturated and omega-3 fats, for saturated fat, show declines in testosterone levels. So it appears that the suggestions related to fat intake and the prevention of cardiovascular disease, such as substituting good fats for bad, may not be the best advice for building muscle. Apparently you need some saturated fat for optimal testosterone synthesis. The suggestion is to take in at least 15 to 20 percent of total calories as dietary fat, with about 10 percent, coming from saturated fat. ALL Research shows that eating mixtures of protein and carbs prior to and following intense training favors an anabolic response in muscle. The amounts usually suggested, however, are laughable. Some studies suggest six to 10 grams of protein combined with 35 grams of simple, or high-glycemic-index, carbs. More protein than that wouldn’t hurt and would probably amplify any anabolic effect.
To maximize muscle glycogen replenishment in muscle following training, the suggestion is to eat 1.2 grams of simple carbs per kilogram of bodyweight at 30-minute intervals for four hours after a workout. An unanswered question is whether that technique has any impact on long-term glycogen replenishment, 24 to 48 hours after a workout.
The authors suggest that attempting to lose bodyfat on a low-carb diet may lead to muscle loss. They feel that you need adequate carbs to power the intense training required for maintaining muscle under dieting conditions. On the other hand, you need increased protein because when you restrict calories, protein is diverted to energy pathways. What’s more, the thermic effect of protein helps foster bodyfat loss while you’re dieting. As you get lean, you need to make sure you don’t cut calories too much. That’s a mistake many bodybuilding competitors make. In an effort to appear as defined as possible, they either do excessive aerobics or cut too many calories or both. That leads to a stringy, catabolic appearance that some refer to as looking flat. IM
1 Lambert, C.P., et al. (2004). Macronutrient considerations for the sport of bodybuilding. Sports Medicine. 34Z:317-27.