Serum leptin and total dietary energy intake: the INTERLIPID Study

It has been hypothesized that leptin-induced appetite suppression is impaired in obese individuals, but little human evidence is available documenting this. We investigated relations between serum leptin and total energy intake using INTERLIPID/INTERMAP data on Japanese-Americans in Hawaii and Japanese in Japan.

Serum leptin and nutrient intakes were examined by standardized methods in men and women aged 40-59 years from two population samples, one Japanese-American in Hawaii (88 men, 94 women), the other Japanese in central Japan (123 men, 111 women). Multiple linear regression analyses stratified by BMI category (<25 kg/m(2), 25-29.9 kg/m(2), and ≥ 30 kg/m(2)) with adjustment for possible confounders were used to examine the relation between log-leptin and total dietary energy intake.

In multivariate regression analyses, in those with BMI < 25 kg/m(2) and in those with BMI between 25 and 29.9 kg/m(2), log-leptin was not significantly related to total dietary energy intake; in those with BMI ≥ 30 kg/m(2), it was significantly inversely related to total dietary energy intake (P = 0.029), independent of body weight and physical activity. Physical activity score was significantly positively related to total dietary energy intake only in participants with BMI < 25 kg/m(2) (P < 0.001).

Leptin was significantly inversely associated with dietary energy intake in obese persons, but not in overweight and normal-weight persons.