Weight Issues

There is no question that total body weight is an important issue for athletes because it influences how easily they can perform their skills. A study assessing the relationships between body composition and fundamental movement skills among children and adolescents found that unhealthy weight gain reduced movement skill.¹ However, looking at weight by itself may provide athletes with a misleading picture of what is good or bad about their body composition. In a number of sports, athletes will increase the time or intensity of a training regimen to improve performance, but then they inappropriately use changes in weight as a marker of success or failure. Imagine a football player who comes to training camp at a weight much higher than the coach is accustomed to seeing in this player. It may well be that the football player worked hard during the off-season to increase muscle mass, and the increase in weight is a result of more muscle. Wouldn's the coach be wrong in telling that player that he has to lose weight? Gymnasts often reach their competitive peak during adolescence, a time when fast growth is the normal biological expectation. Despite this, gymnasts and other athletes are often weighed weekly or more often to make certain they are maintaining their weight. Shouldn't all the training they've doing increase their muscle mass and therefore their weight? Shouldn't they be growing and thus increasing their weight? These are examples of how weight is often used arbitrarily and incorrectly. Tracking the constituents of weight makes much more sense and provides valuable information on the nature of body changes that are occurring.

The principle of energy thermodynamics is always with us. Consumption of more calories than the body burns leads to a weight gain; consumption of fewer calories than the body burns leads to a weight loss; and consumption of exactly the same number of calories that the body burns leads to weight stability. But making a change in body weight is not as straightforward as the principle of energy thermodynamics may make it appear to be.

The most common belief is that low-calorie dieting is an effective but unpleasant means of weight and fat loss. It seems logical that a 25 percent reduction in energy intake will lead to a 25 percent reduction in weight. The reality, however, is that energy expenditure after weight loss is less than would be expected by the amount of weight that was lost.4 This means that the adjustment in energy expenditure to inadequate intake is greater than the mathematical expectation and leads to a return to the original weight, even with a lower energy intake (i.e., the less you eat, the less you can eat to maintain weight). A close look at the reason for this lower metabolic rate is clear. With an inadequate caloric intake, the body catabolizes the metabolic (lean) mass so it can survive on less energy.

Logic also suggests that a 25 percent increase in energy intake will lead to a 25 percent increase in weight. In fact, although weight gain does occur, it doesn't appear to increase as much as the increase in energy intake suggests it should, but it's close. When people are purposefully overfed to gain weight, the amount of weight gain is proportionate to the amount of overfeeding.5-8 These studies strongly suggest that we have homeostatic mechanisms during periods of energy deficit that help us maintain our weight. This may be a"survival of the species"mechanism that helps humans survive periods of famine. We also appear able to store energy effectively (as fat) during periods of excess. This may be another survival mechanism that enables us to store energy when we are lucky enough to have excess food available.

Since major energy surpluses and deficits appear to activate homeostatic mechanisms, a possible means of making a desired change in weight and body composition is to avoid major energy-balance shifts. Exercise should be at the core of any desired body composition change (i.e., an increase in lean mass and a decrease in fat mass, coupled with a small decrease in weight). But such a change might be easier to achieve if the energy deficit and energy surplus created are never too large during the day. Energy surpluses and deficits are represented, respectively, by variations above and below the perfect energy-balance line (zero). In the figure, when the line moves above zero, the athlete has consumed more energy than was expended. When the line moves below zero, the athlete has expended more energy than was consumed. Eating pattern 1 represents an athlete eating small meals frequently; there are no energy surpluses or deficits that exceed 400 calories. Eating pattern 2 represents infrequent eating, with excess calories (high surplus energy peaks) consumed at each meal. Eating pattern 3 represents an athlete who spends the majority of the day in an energy-deficit state from not eating enough when the energy is needed, a condition that stimulates the breakdown of muscle tissue for energy. At the end of the day, a very large meal brings the athlete into energy balance, but much of this meal will be stored as fat. Within any given day, energy balance is important for both performance and body composition.

Weight is the best indicator of the adequacy of caloric intake, and body composition helps determine if the calories are being consumed in the proper amounts and at the correct intervals.

Since the standard three-meal-a-day schedule forces athletes to consume a large amount of energy at each meal to obtain the necessary energy, staying in energy balance is easier on a six-meal pattern. Frequent consumption of small meals to maintain a steady energy flow can be an important strategy in making the desired changes.

Figure 12.2 An individual's eating pattern has the potential to greatly affect body composition.