부산대학교 도서관

Objective Although obesity is associated with metabolic dysfunction and ectopic fat accumulation, it is unknown whether overfeeding and a moderate increase in body weight in obese subjects results in additional adverse effects on metabolic function and fat distribution. Therefore we evaluated the effect of overfeeding an additional 1000 kcal/day from fast food restaurants on insulin sensitivity and ectopic fat distribution in 11 obese subjects (1 male, age = 44 ± 10 y, BMI = 34 ± 3 kg/㎡). Methods A two-stage (7 and 50 mU/㎡/min) hyperinsulinemic-euglycemic clamp procedure in conjunction with stable isotope tracer infusion was used to assess hepatic and skeletal muscle insulin sensitivity. Magnetic resonance (MR) spectroscopy, MR-elastography and MR-imaging were used to measure intrahepatic triglyceride (IHTG) content and stiffness, and visceral adipose tissue [VAT], respectively. These measurements were obtained at baseline and after a 6 ± 1% (5 ± 1 weeks) weight gain was achieved. Results Overfeeding caused an increase in total body fat (12±4%), fat-free mass (2 ± 1%), and VAT (10 ± 13%) (all P-values < 0.05). IHTG content increased by 83 ± 51% (from 8 ± 11% to 12 ± 11%, P < 0.01), and liver stiffness (index of hepatic fibrosis) increased by 16 ± 22% (from 2.9 ± 0.4 kPa to 3.2 ± 0.6 kPa, P < 0.05). Hepatic insulin sensitivity, measured as the % suppression of endogenous glucose production during low-dose insulin infusion, decreased from 71 ± 10% to 64 ± 13% (P = 0.05). Skeletal muscle insulin sensitivity, measured as the % increase in glucose uptake during high-dose insulin infusion, decreased from 321 ± 124% to 248 ± 117%, (P < 0.05). Conclusion These results demonstrate that overfeeding with moderate weight gain in already obese subjects causes further adverse effects on fat distribution and insulin sensitivity.