Hormones play a significant role in fitness and weight management. Key hormones, including insulin, cortisol, and leptin, influence metabolism and energy regulation. For instance, insulin helps control blood sugar levels and fat storage, while cortisol, a stress hormone, can affect hunger and fat distribution. Leptin, produced by fat cells, signals fullness to the brain, regulating appetite. Balancing these hormones through proper nutrition, exercise, and lifestyle choices can significantly impact weight loss and overall fitness success.