Fructose and Sucrose Intake Increase Exogenous Carbohydrate Oxidation during Exercise

Nutrients. 2017 Feb 20;9(2):167. doi: 10.3390/nu9020167.

Abstract

Peak exogenous carbohydrate oxidation rates typically reach ~1 g∙min-1 during exercise when ample glucose or glucose polymers are ingested. Fructose co-ingestion has been shown to further increase exogenous carbohydrate oxidation rates. The purpose of this study was to assess the impact of fructose co-ingestion provided either as a monosaccharide or as part of the disaccharide sucrose on exogenous carbohydrate oxidation rates during prolonged exercise in trained cyclists. Ten trained male cyclists (VO2peak: 65 ± 2 mL∙kg-1∙min-1) cycled on four different occasions for 180 min at 50% Wmax during which they consumed a carbohydrate solution providing 1.8 g∙min-1 of glucose (GLU), 1.2 g∙min-1 glucose + 0.6 g∙min-1 fructose (GLU + FRU), 0.6 g∙min-1 glucose + 1.2 g∙min-1 sucrose (GLU + SUC), or water (WAT). Peak exogenous carbohydrate oxidation rates did not differ between GLU + FRU and GLU + SUC (1.40 ± 0.06 vs. 1.29 ± 0.07 g∙min-1, respectively, p = 0.999), but were 46% ± 8% higher when compared to GLU (0.96 ± 0.06 g∙min-1: p < 0.05). In line, exogenous carbohydrate oxidation rates during the latter 120 min of exercise were 46% ± 8% higher in GLU + FRU or GLU + SUC compared with GLU (1.19 ± 0.12, 1.13 ± 0.21, and 0.82 ± 0.16 g∙min-1, respectively, p < 0.05). We conclude that fructose co-ingestion (0.6 g∙min-1) with glucose (1.2 g∙min-1) provided either as a monosaccharide or as sucrose strongly increases exogenous carbohydrate oxidation rates during prolonged exercise in trained cyclists.

Keywords: substrate utilization; metabolism; stable isotopes; sugar.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Bicycling
  • Blood Glucose / metabolism
  • Body Mass Index
  • Body Weight
  • Cross-Over Studies
  • Diet
  • Dietary Carbohydrates / administration & dosage
  • Dietary Carbohydrates / metabolism*
  • Double-Blind Method
  • Exercise*
  • Fructose / administration & dosage*
  • Glucose / administration & dosage
  • Humans
  • Insulin
  • Lactic Acid / blood
  • Male
  • Oxygen Consumption*
  • Sucrose / administration & dosage*

Substances

  • Blood Glucose
  • Dietary Carbohydrates
  • Insulin
  • Fructose
  • Lactic Acid
  • Sucrose
  • Glucose