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

Abstract

Objective: To examine the relationship between fasting plasma leptin and 24-hour energy expenditure (EE), substrate oxidation, and spontaneous physical activity (SPA) in obese subjects before and after a major weight reduction compared with normal weight controls. To test fasting plasma leptin, substrate oxidations, and SPA as predictive markers of success during a standardized weight loss intervention. Research Methods and Procedures: Twenty-one nondiabetic obese (body mass index: 33.9 to 43.8 kg/m 2 ) and 13 lean (body mass index: 20.4 to 24.7 kg/m 2 ) men matched for age and height were included in the study. All obese subjects were reexamined after a mean weight loss of 19.2 kg (95% confidence interval: 15.1-23.4 kg) achieved by 16 weeks of dietary intervention followed by 8 weeks of weight stability. Twenty-four-hour EE and substrate oxidations were measured by whole-body indirect calorimetry. SPA was assessed by microwave radar. Results: In lean subjects, leptin adjusted for fat mass (FM) was correlated to 24-hour EE before (r ϭ Ϫ0.56, p Ͻ 0.05) but not after adjustment for fat free mass. In obese subjects, leptin correlated inversely with 24-hour and resting nonprotein respiratory quotient (r ϭ Ϫ0.47, p Ͻ 0.05 and r ϭ Ϫ0.50, p Ͻ 0.05) both before and after adjustments for energy balance. Baseline plasma leptin concentration, adjusted for differences in FM, was inversely related to the size of weight loss after 8 weeks (r ϭ Ϫ0.41, p ϭ 0.07), 16 weeks (r ϭ Ϫ0.51, p Ͻ 0.05), and 24 weeks (r ϭ Ϫ0.50, p Ͻ 0.05). Discussion: The present study suggests that leptin may have a stimulating effect on fat oxidation in obese subjects. A low leptin level for a given FM was associated with a greater weight loss, suggesting that obese subjects with greater leptin sensitivities are more successful in reducing weight.

Is serum leptin related to physical function and is it modifiable through weight loss and exercise in older adults with knee osteoarthritis?

“…Verdich also showed that leptin was inversely related to weight loss in 28-39-year old men, indicating that an increase in leptin sensitivity was associated with greater weight loss. 30 Moreover, in a prospective analysis of the Health Professionals Follow-Up Study of overweight men, weight gain over 4 years was associated with a high leptin level. 53 In conclusion, the weight loss intervention utilized in this study produced significant changes in body weight and in leptin concentrations at the 6-and 18-month follow-up.…”

“…40 These studies demonstrate that leptin is involved in the regulation of body energy balance. 30,41 Recent evidence hints that leptin may be involved in certain disease states. Levels of this hormone are elevated in synovial Leptin, weight loss, and exercise GD Miller et al fluid in patients with OA compared to normal controls.…”

“…The nearly 25% drop in leptin observed at 6 months was considerably less than the 50% decrease reported by others, although this may be related to the greater weight loss observed in those studies. 30,[45][46][47] For example, a very low calorie diet (800 kcals day À1 ) over a 10-week period produced a 13.6% decrease in body weight with a 50% drop in serum leptin levels. 48 These participants were nearly 20 years younger and much heavier than those in the current study with an average BMI of 50 kg m À2 .…”

“…In contrast, other studies in obese children and young men and women show that low plasma leptin levels are predictive of weight loss, suggesting a greater sensitivity to circulating serum leptin. [29][30][31][32] Identifying biological predictors of weight loss may aid in devising interventions that directly affect biomarkers and provide success in weight management for OA patients.…”

Adaptations in Mitochondrial Function Parallel, but Fail to Rescue, the Transition to Severe Hyperglycemia and Hyperinsulinemia: A Study in Zucker Diabetic Fatty Rats

“…As fa/fa rats lack the leptin receptor and leptin stimulates skeletal muscle fat oxidation (26,27), the reduced fat oxidative capacity at early age in fa/fa rats might be due to the ablation of the leptin receptor. This makes this model suitable to investigate the consequence of reduced fat oxidation on the development of type 2 diabetes.…”