Why bodybuilders gain weight after a contest

When people return to their previous eating and activity habits after losing weight, their body fat tends to increase back to the level it was before the weight loss.

In natural physique athletes, levels of thyroid hormones decrease during competition preparation and return to normal within 12 weeks after the competition, suggesting that thyroid function recovers after the stress of dieting and training, though this recovery may occur more slowly than changes in body composition or metabolism.

After competitive bodybuilding, natural athletes regain muscle mass and metabolic rate quickly, mostly within 12 weeks; continuing very low-calorie diets beyond this time may slow down the body's return to normal function.

In competitive athletes, psychological symptoms such as mood swings and disordered eating behaviors are most severe during training for a competition and show significant improvement 12 weeks after the event, suggesting that mental health recovery takes longer than physical recovery and may need targeted intervention.

After competing in natural bodybuilding, athletes typically regain muscle mass and their resting metabolism increases over 12 weeks, with muscle mass rising by about 1.6 kg on average, suggesting this recovery is due to more than just fat gain—it also involves rebuilding muscle and stored water from glycogen.