Widespread practice among athletes harms both health and performance

Reducing caloric intake for weight loss before competitions is common among athletes but can impair performance and weaken the immune system. This practice, prevalent in endurance sports like running, swimming, cycling, and rowing, aims to enhance performance or meet weight categories. A study with twelve female triathletes showed that consuming 50% of their caloric needs for 14 days led to a 4% weight loss and reduced performance by 7.7% in a 20-minute cycling trial and 18% in a shorter, intense test. This calorie restriction also increased cortisol levels and stress in immune cells, suggesting a weakened immune system and higher illness risk. Team Denmark supports these findings, emphasizing the need to reconsider the "lighter is better" mentality. Research also indicates that women are more vulnerable to the effects of low energy intake compared to men, partly due to significant drops in estrogen, which affects overall physiology.