Dieting
In addition to improving performance through healthy eating, some athletes will seek to lose weight through dieting and aerobic exercise. By losing fat they hope to achieve a higher "strength to mass ratio" or "lean weight." This means more muscle and less fat, and should theoretically give them an advantage against other athletes of the same weight.
Healthy weight loss can be seen as a positive effect of participation in sports, but reducing body fat too greatly can cause health problems. Athletes should try to maintain their body fat at the lowest healthy level to achieve their best performance.
Athletes at the elite level will sometimes attempt to temporarily lower their body fat to unhealthy levels to give themselves an edge in important competitions. Afterwards they will regain the lost fat, and return to their normal training weight. This technique should not be attempted without knowledge of periodization and the help of a knowledgeable coach and medical advice.
Children and teenagers should be cautioned to avoid losing weight at excessive quick rates or to excessively low levels the way adult athletes may choose to. Young bodies require additional nutrients to grow. Weight-cutting techniques can interfere with healthy physical development.
Read more about this topic: Weight Cutting