Weight cutting is the practice of rapid weight loss before a sports competition. It happens most often to qualify for a lower weight category (usually in combat sports, where weight is a significant advantage) or in sports where it is advantageous to weigh as little as possible (including equestrian sports). There are two types of weight cutting: One method is to lose weight in the form of fat and muscle in the weeks leading up to an event; the other is losing weight in the form of water in the last days before the competition. Nutrition experts will rarely give advice on how to reduce weight safely or effectively, and simply recommend not to cut weight at all. However, many athletes choose to do so because they want an advantage in their sport.
In addition to improving performance through healthy eating, some athletes will try to lose weight by 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 theoretically should give them an advantage against other athletes of the same weight.