Leptin is the satiety hormone—released by fat cells to tell the brain “we have enough energy stored.” Research by Friedman discovered leptin in 1994, but subsequent studies found that people with obesity often have high leptin levels—the problem is leptin resistance, where the brain doesn’t hear the signal. Despite abundance, the brain perceives starvation. The fix isn’t more leptin but restoring sensitivity.
This companion covers leptin’s intended function, the resistance problem, what causes it, and how to address it. (4 min read)