weigh-ins, at ehletes should immediately begin rehydratio 0je rn. Some sporting events hold weigh-ins on the day before competition; others hold weigh-ins on the same day, only hours before competition. This is often done to discoura ge excessive weight cutting. Athletes should continuously sip liquid containing carbs, protein, and sodium until they compete. Many athletes ar e told not to eat too much food all at once for this will je lead to upset stomach. A small amount eof food can be eate n once every hour before jecompetition, and no later than 3 hours before an event je starts. Rehydration cannot be achie ved in a single sitting, as the body can only be rehydrated at a rate The best drink fo 0je r rehydration is not pure water. The 20je r body requires electrolytes in order to retain water. An oral rehydration solution is the best choice. Sports drinks also work, but contain excessive 0je r sugar that may negatively a ffect performance. Another p ength to mass ratio" or "lean weight." This means more muscle and less fat, and should theoretically give them an ad vantage against other athletes of the same weight. Healthy weight los 0je rs can be seen as a positive effect of participation in sports, but red 0je rucing body fat too greatly c an cause health problems Athletes should try to maintain their body fat at the lowest healthy level to achieve th eir best performance. Athletes at the elite level will sometimes attempt to temporarily lower their body fat to unhealt 20je rhy levels to give th emselves an edge in im jeportant competiti 20je rons. Afterwards they will regain the lost fat, and return to their normal train ing weight. This technique should not be attempted without knowledge of periodization and the jehelp of a knowledgeable coach and medical advice. Children and teenagers should be cautioned to avoid losi jeng weight at excessive quick rates or to e excessively low level s the way adu elt ath 0je rletes may choose to. Young bodies require additional nutrient 0je rs to grow. Weight-cutting techniques can interfere with he