Free fatty acid-induced hepatic insulin resistance is attenuated following lifestyle intervention in obese individuals with impaired glucose tolerance.

Description

In this study, the authors sought to examine the effects of an exercise/diet lifestyle intervention on free fatty acid (FFA)-induced hepatic insulin resistance in obese humans. A total of 23 older (66 ± 1yr), obese (34 ± 1 kg/m2) men and women with impaired glucose tolerance were entered into a 12-wk lifestyle intervention program. The subjects were randomly assigned to either exercise training with eucaloric (EU; ~1800 kcal; n=11) or hypocaloric (HYPO; ~1300 kcal; n=12) diet for 12 weeks. Both lifestyle interventions reduced hepatic insulin resistance under basal and hyperinsulinemic conditions. However, the combined exercise/diet intervention was more effective in reversing FFA-induced hepatic insulin resistance than exercise alone and this positive effect was related to significant decreases in central adiposity. Moreover, both interventions showed an improvement in the insulin’s ability to suppress hepatic glucose production during hyperinsulinemia, but the FFA-induced hepatic glucose production during hyperinsulinemia was only improved in the HYPO group. Thus, these results suggest that exercise alone cannot prevent hepatic insulin resistance in patients with elevated FFA levels.