For many athletes, and also those who seek physique enhancement, weight loss is often the primary goal of a combined training and nutrition regimen, especially in sports such as wrestling, boxing, and weightlifting, in which stringent body weight requirements necessitate weight loss in many cases.
Likewise, in sports such as gymnastics and distance running, in which there are no weight limitations, low body fat levels are considered optimal for performance.
Indeed, weight and body fat loss is frequently the primary objective for anyone pursuing physique improvement. In pursuit of weight loss, many individuals, including athletes, adopt nutritional principles that are ineffective and potentially harmful.
For instance, drastically reducing caloric intake is not only associated with a reduction in performance, but it can also cause adverse changes in vitamin and mineral status. Accordingly, improper rates of weight loss can encourage a loss of lean body mass and glycogen stores, and increase the likelihood of dehydration.
Simultaneously losing body fat and gaining lean body mass is possible through appropriate training and caloric restriction. However, in the case of the individual who has a relatively low body fat content before losing weight it is possible that reductions in lean body mass will accompany fat losses.
Additionally, large and/or rapid weight reductions following caloric restriction likewise result in losses of lean body mass. Therefore, to counteract the potential for muscular losses and a subsequent decrease in metabolic rate during caloric restriction, resistance training and an increase in dietary protein should accompany.
Note that initial weight loss incurred from undergoing caloric restriction is mostly water loss, especially within the first 3 days. In fact, as much as 70% of weight loss achieved through reducing calories by 1000 kcal/day can be attributed to water.
As a general guideline, an acceptable rate of weight loss appears to be approximately 1% per week, which can be achieved through a caloric deficit of 500 to 1000 kcal/day. Because 3500 kcal comprise 0.45 kg (1.0 lb.) of fat, weight reductions should proceed at, but not surpass, 0.51.0 kg/wk.
The most effective approach to weight loss involves a regimen that both reduces dietary caloric intake and also burns calories through exercise. Numerous studies have shown that adding exercise to a weight loss program results in a greater loss of body fat, while maintaining or increasing lean body mass.
For example, a program of weight control that expended 250 kcal daily through exercise and an additional 250 kcal through dietary restriction would be more effective than a program that simply limited caloric intake by 500 kcal. Furthermore, when weight is reduced by diet alone, there is a greater likelihood that there will be a loss of lean tissue, subsequently promoting a drop in resting metabolic rate.