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


METHODS
Twenty-two normal-weight men and women (age: 21.2±0.6 years; body mass index: 22.6 ±0.6 kg/m(2)) 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 × 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.
1] Department of Health Promotion and Wellness, State University of New York at Oswego, Oswego, NY, USA [2] Department of Exercise Science, Syracuse University, Syracuse, NY, USA.
A J
AJ
Bidwell
School of Psychology and Exercise Science, Murdoch University, Perth, Western Australia, Austrailia.
T J
TJ
Fairchild
Department of Family and Consumer Sciences, California State University, Long Beach, CA, USA 
L
L
Wang
Department of Exercise Science, Syracuse University, Syracuse, NY, USA.
S
S
Keslacy
Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, USA.
J A
JA
Kanaley
D000328:Adult; D019540:Area Under Curve; D001786:Blood Glucose / Q000378:metabolism*; D002097:C-Reactive Protein / Q000378:metabolism*; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000378:metabolism / Q000494:pharmacology; D015444:Exercise / Q000502:physiology*; D005260:Female; D005632:Fructose / Q000378:metabolism / Q000494:pharmacology*; D005749:Gastric Inhibitory Polypeptide / Q000097:blood*; D052216:Glucagon-Like Peptide 1 / Q000097:blood*; D006801:Humans; D007328:Insulin / Q000097:blood*; D008297:Male; D019518:Postprandial Period; D012016:Reference Values; D012737:Sex Factors; D055815:Young Adult
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D007328:Insulin; D005632:Fructose; D005749:Gastric Inhibitory Polypeptide; D052216:Glucagon-Like Peptide 1; D002097:C-Reactive Protein