Serum leptin levels and energy expenditure in normal weight women

Abstract

To investigate whether circulating leptin levels are associated with energy expenditure in healthy humans, doubly labeled water energy measurements and food intake assessment were carried out in 27 women (mean age, 48.6 years; weight, 61.9 kg; body mass index, 23.2). Energy expenditure was determined over 13 days. Food intake was measured by 7-day food records. Leptin was measured by radioimmunoassay. Leptin level was strongly associated with percentage body fat (r = 0.59; p < 0.001), fat mass (r = 0.60; p < 0.001), and body mass index (r = 0.41; p = 0.03), but no correlation was observed with energy expenditure (r = 0.02; p = 0.93). After controlling for percentage body fat, a positive association of leptin level with energy expenditure of marginal significance (p = 0.06) was observed. There were no significant univariate associations of age, physical activity, lean body mass, height, or dietary variables with leptin level. When controlling for body fat, a significant positive correlation was observed for percent energy from carbohydrate and negative correlations with dietary fat and alcohol intake. These findings confirm previous associations between leptin and body fat content and suggest a relationship between serum leptin and energy expenditure level in healthy humans.

Effects of short-term carbohydrate or fat overfeeding on energy expenditure and plasma leptin concentrations in healthy female subjects

“…In humans, a relationship between plasma leptin concentrations and energy expenditure has been observed. 30 Our present observation indicates that carbohydrate overfeeding increases fasting leptin concentrations, but not basal energy expenditure. There was also no correlation between changes in fasting leptin concentration and in 24 h EE.…”

Leptin Levels Are Associated with Fat Oxidation and Dietary‐Induced Weight Loss in Obesity

“…However, these correlations were found to be independent of changes in body composition only in the study of Doucet et al (45). A positive association between leptin and EE has been described previously in cross-sectional studies pertaining to humans (17)(18)(19)(20)(21). In one study, however, leptin was not controlled for differences in FM (18).…”

“…However, in a group of lean and obese 5-year-old Pima Indian children, Salbe et al (17) found that fasting leptin concentration was correlated positively and independently with both total EE assessed by doubly labeled water and with physical activity level. In another study, a nearly significant positive relationship was seen between leptin and EE under free-living conditions in women, after adjusting for differences in body fat percentage (19). Recently Jørgensen and colleagues (21) showed that, in men, leptin is a stronger positive determinant of resting metabolic rate than is FM, whereas the opposite is seen in women.…”

“…Findings from some previous studies in humans have supported the hypothesis of a role of leptin in stimulating EE (7,(17)(18)(19)(20)(21), whereas others have failed to find such relationship (22)(23)(24)(25). Furthermore, inverse correlations between fasting plasma leptin and resting metabolic rate have been reported in obese subjects, in contrast to lean individuals, supporting the hypothesis of leptin-resistance in obesity (26 -28).…”

Differential and genetically separable associations of leptin with obesity-related traits

“…leptin (10 mgakgaday for 3 weeks) increased physical activity levels in leptinde®cient obese obaob mice. 21 However, most studies in human subjects have found no relationship between leptin and physical activity levels, 22,23 with only one study in children showing a positive relationship. 24 The apparent inability of leptin to in¯uence physical activity in adult human subjects is also illustrated in a recent study that has shown that the activation of spontaneous physical activity in subjects who are resistant to weight gain after overfeeding is not mediated by leptin.…”