Abstract
BACKGROUND: Adipose tissue functions as an endocrine organ by releasing adipokines which have important roles in the regulation of inflammation and insulin sensitivity. Although there is evidence of improvement in circulating levels of adipokines with weight loss, few studies relate such changes to specific diets. We investigated the effects of weight loss achieved by two different diets on circulating adipokine levels in obese individuals. METHODS: A total of 120 obese patients (body mass index ≥ 35 kg/m(2)) underwent a three-month screening period on a low-fat, reduced-calorie diet. Patients failing to achieve a 5% weight loss using this approach were randomly allocated to either a low carbohydrate/high protein diet (n = 17) or to a commercial very low calorie diet (LighterLife(®), n = 14) for a period of nine months. RESULTS: At nine months, a significant weight loss was only maintained for Lighter-Life(®) (-32.3 ± 22.7 kg, P < 0.0001) but not on the low carbohydrate/high protein diet. Changes in adiponectin (15.8 ± 17.1 ng/mL versus -0.8 ± 6.2 ng/mL, P = 0.003) and leptin (-17.6 ± 24.3 ng/mL versus -3.0 ± 9.2 ng/mL, P = 0.049) at nine months were significantly greater for LighterLife(®) than for the low carbohydrate/high protein diet, which may reflect greater weight loss and decrease in fat mass. Changes in tumor necrosis factor-alpha, interleukin-6, and plasminogen activator inhibitor type 1 did not differ significantly between the dietary interventions at nine months. CONCLUSION: A significant weight loss of 23.8% from baseline weight was observed using a very low calorie diet and resulted in significant improvements in circulating levels of leptin, plasminogen activator inhibitor type 1, and adiponectin, which are likely to be due to weight loss and not macronutrient intake.