Consumption of fructose-sweetened beverages for 10 weeks reduces net fat oxidation and energy expenditure in overweight/obese men and women

BACKGROUND/OBJECTIVES: The results of short-term studies in humans suggest that, compared with glucose, acute consumption of fructose leads to increased postprandial energy expenditure and carbohydrate oxidation and decreased postprandial fat oxidation. The objective of this study was to determine the potential effects of increased fructose consumption compared to isocaloric glucose consumption on substrate utilization and energy expenditure following sustained consumption and under energy-balanced conditions. SUBJECTS/METHODS: As part of a parallel arm study, overweight/obese male and female subjects, 40–72 y, consumed glucose- or fructose-sweetened beverages providing 25% of energy requirements for 10 weeks. Energy expenditure and substrate utilization were assessed using indirect calorimetry at baseline and during the 10(th) week of intervention. RESULTS: Consumption of fructose, but not glucose, led to significant decreases of net postprandial fat oxidation and significant increases of net postprandial carbohydrate oxidation (P < 0.0001 for both). Resting energy expenditure decreased significantly from baseline values in subjects consuming fructose (P = 0.031) but not in those consuming glucose. CONCLUSIONS: Increased consumption of fructose for 10 weeks leads to marked changes of postprandial substrate utilization including a significant reduction of net fat oxidation. In addition, we report that resting energy expenditure is reduced compared to baseline values in subjects consuming fructose-sweetened beverages for 10 weeks.