Effect of increased physical activity on fructose-induced glycemic response in healthy individuals

Abstract

BACKGROUND/OBJECTIVES: The purpose of the current study was to determine whether increased physical activity (PA) altered glycemic control while ingesting an energy-balanced high-fructose diet. SUBJECTS/METHODS: Twenty-two normal-weight men and women (age: 21.2 ± 0.6 years; body mass index: 22.6 ± 0.6 kg/m2) participated in a randomized, cross-over design study in which they ingested an additional 75 g of fructose for 14 days while either maintaining low PA (FR+inactive) (< 4500 steps/day) or high PA (FR+active) (>12 000 steps/day). Before and following the 2-week loading period, a fructose-rich meal challenge was administered and blood was sampled at baseline and for 6 h after the meal and analyzed for glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), c-peptide, glucose and insulin concentrations. RESULTS: Plasma insulin, glucose, c-peptide, GIP and GLP-1 concentrations significantly increased in response to the test meal on all test visits (P<0.05). C-peptide incremental area under the curve (AUC) decreased by 10 208 ± 120 pmol/l x min for 6 h from pre to post Fr+active intervention (P = 0.02) leading to a decrease in plasma insulin total AUC (pre: 58 470.2 ± 6261.0 pmol/l; post: 49 444.3 ± 3883.0 pmol/l; P = 0.04) resulting in a decrease Δpeak[Insulin] (P = 0.009). Following the FR+active intervention, GIP total AUC significantly decreased (P = 0.005) yet only males had a lower total GLP-1 AUC after both interventions (P = 0.049). There were no sex differences in GIP levels. CONCLUSIONS: Increased PA attenuates the deleterious effects on glycemic control caused by a high-fructose diet. These changes in glycemic control with PA are associated with decreases in insulin and GIP concentrations.