Abstract

Objective Central obesity is associated with insulin resistance through factors that are not fully understood. We studied the effects of three different isocaloric diets on body fat distribution, insulin sensitivity and peripheral adiponectin gene expression.

Research Design and Methods Eleven volunteers, offspring of obese type 2 diabetic patients with abdominal fat deposition were studied. These subjects were considered insulin resistant as indicated by their Matsuda Index < 4 after OGTT and they maintained HBA1c < 6.5% without therapeutic intervention. All subjects underwent three dietary periods of 28 days each in a crossover design: a) diet enriched in saturated fat (SAT), b) diet rich in monounsaturated fat (MUFA; Mediterranean diet) and c) diet rich in carbohydrates (CHO).

Results Weight, body composition and resting energy expenditure remained unchanged during the three sequential dietary periods. Using dual-energy X-ray absorptiometry we observed that when patients were fed a CHO-enriched diet their fat mass was redistributed towards the abdominal depot while periphery fat accumulation decreased compared with isocaloric MUFA-rich and high SAT diets (ANOVA < 0.05, respectively). Changes in fat deposition were associated with decreased postprandial mRNA adiponectin levels in peripheral adipose tissue and lower insulin sensitivity indices (SI) from a frequently sampled insulin-assisted intravenous in patients fed a CHO-rich diet compared with a MUFA-rich diet (ANOVA < 0.05, respectively).

Conclusions An isocaloric MUFA-rich diet prevents central fat redistribution and postprandial decrease in peripheral adiponectin gene expression and insulin resistance induced by a carbohydrate-rich diet in insulin-resistant subjects.