Background: On the basis of observations in rodents, leptin is thought to play a key role in the regulation of energy expenditure and food intake, but less is known of its influence on ingestive behavior and energy balance in humans.
Objective: We examined the effect in women of a chronic energy deficit on plasma leptin concentrations and self-reported appetite and explored possible relations between leptin and appetite sensations.
Design: Twelve healthy women (body mass index, in kg/m2: 23-37) participated in a metabolic ward study in which 3 wk of neutral energy balance was followed by 12 wk of energy deficit (energy intake reduced by 2 MJ/d and energy expenditure increased by 0.8 MJ/d). Body weight and composition were monitored, fasting leptin concentrations were measured 4 times, and feelings of hunger, fullness, desire to eat, and prospective consumption were monitored hourly throughout the day on 7 selected days.
Results: Adiposity-adjusted leptin decreased by 54% after 1 wk of a moderate energy deficit and remained low after 6 and 12 wk. Leptin was associated with self-reported hunger, desire to eat, and prospective consumption (range of r: -0.6 to -0.7, P < 0.01). The greatest hunger increase coincided with the largest percentage drop in circulating leptin and the lowest final leptin concentration. The relation between leptin and hunger was not influenced by amount of weight or body fat loss.
Conclusions: These findings support the idea that leptin is a physiologic regulator of hunger during energy deficits in humans; the role of leptin in the long-term regulation of food intake warrants further study.