Consequences of body weight rapid reduction in athletes of combat sports and the importance of nutrition: a review

The combat sports are usually divided by weight categories. In order to gain an advantage by struggling with lighter and weaker opponents, many athletes often reduce their body weight quickly through potentially dangerous strategies. The objective of this review was to systematize the main findings of the literature regarding the consequences of the practice of rapid weight reduction on physiological systems and performance, as well as to verify the importance of nutrition in this context. The literature review included national and international publications, with dates between January 1970 and May 2017, in the electronic databases: Elsevier, Medline, Pubmed, Scopus, Sportdiscus and Web of Science. Key words used in the search were included in the Thesaurus Medical Subject Headings (MeSH) developed by the U.S. National Library of Medicine. The scientific literature was unanimous in demonstrating the effects on the physiological systems, such as: reduction of bone density; Increased development of eating disorders; Depression of the immune system; Dysfunctions of the cardiovascular system and hyperthermia. Regarding performance, there is consensus in the literature that rapid weight reduction decreases aerobic performance. However, the effects on anaerobic performance are still divergent as they depend on the time between weighing and fighting. Several studies have shown that eating habits decisively affect health, weight, body composition and sports performance, and nutritional interventions are effective in reducing weight gradually by reducing total caloric intake.