Your body defends a particular weight with surprising persistence. Research by Leibel and Rosenbaum shows that when you lose weight, metabolic rate drops, hunger hormones increase, and energy expenditure decreases — all pushing you back toward previous weight. The “Biggest Loser” study found persistent metabolic suppression years later. You’re not fighting just habits; you’re fighting physiology.
This companion covers evidence for set point, defense mechanisms, evolutionary reasons, whether it can change, and working with your biology. (4 min read)