Extreme dieting poses several risks for fitness, including nutrient deficiencies, muscle loss, and metabolic disturbances. Such diets often lead to a severe reduction in calorie intake, which can slow the metabolism and negatively impact energy levels and exercise performance. Moreover, extreme dieting can foster unhealthy relationships with food, increase the likelihood of binge eating, and result in yo-yo dieting. Balance and moderation are crucial for long-term health and fitness success.