One day of mixed meal overfeeding reduces hepatic insulin sensitivity and increases VLDL particle but not VLDL-triglyceride secretion in overweight and obese men

Abstract

Context: The exact mechanisms responsible for increased plasma triglyceride (TG) concentration in obese people are unclear, and it is not known whether excess energy intake per se is involved in the pathophysiology of this abnormality. Objective: The purpose of our study was to examine how excess energy intake from a balanced diet for 1 day affects very-low-density lipoprotein (VLDL)-TG kinetics and its putative regulators hepatic insulin sensitivity and plasma free fatty acid availability. Subjects and Design: We used stable isotope-labeled tracer methods to evaluate glucose and lipid kinetics in 8 overweight and obese men (age, 38 ± 3 years; body mass index, 33.7 ± 1.7 kg/m2; means ± SEM) on 2 occasions (randomized crossover design): once, the day after they consumed a balanced diet that provided an amount of energy that matched their energy expenditure, and another time, the day after they consumed a balanced diet that provided30%excess calories. Eight healthy, lean men (34 ± 1 years; 22.5 ± 0.6 kg/m2) were studied under isocaloric conditions only to provide a reference for normal lipid kinetics. Results: VLDL-TG and VLDL-apolipoprotein B-100 (apoB-100) concentrations and secretion rates were significantly greater (P