The body defends a weight setpoint like a thermostat defends temperature. Research by Leibel shows when you eat less, the body reduces expenditure and increases hunger to return to setpoint. This is why dieting alone often fails: you’re fighting regulatory systems. Changing the setpoint — through fasting, food quality, time — works with the system instead of against it.
This companion covers the thermostat model, evidence for setpoint, why it’s elevated, and how to change it. (3 min read)