A Comparison of the Effect of Consuming a Fructose-, Glucose-, or Aspartame-Sweetened Beverage on Ad Libitum Caloric Intake

Abstract

Background: The per capita consumption of sugar-sweetened beverages (SSB) has increased in tandem with the obesity epidemic. While many epidemiological and clinical studies have shown a positive association between consumption of SSB and increased risk of weight gain, the exact mechanism by which the consumption of SSB leads to weight gain remains unclear.

Objectives: To determine whether ad libitum caloric intake is differentially affected by consumption of a fructose-, glucose-, or aspartame-sweetened beverage and to determine whether subjects are able to compensate for energy taken up through SSB by reducing their ad libitum intake of solid food.

Design: Nine subjects were randomly assigned to each of the three, eight-day isocaloric dietary periods, which were separated by 20-day washout periods. Order was determined by block randomization. The diet periods differed only in the type of SSB administered to the subjects. Solid food and the SSB were administered to subjects at the beginning of each dietary period. Subjects were asked to consume solid food ad libitum, but were required to consume all four servings of the SSB each day. Ad libitum caloric intake was assessed by weighing and measuring subjects' uneaten food at the end of each dietary period.

Results: Nine healthy, young, normal-weight subjects (4 male, 5 female) completed all three dietary periods. Subjects consumed an average of 2698 ± 607 kcal/day, 2629 ± 682 kcal/day, and 2307 ± 651 kcal/day during the fructose-, glucose-, and aspartame-diet periods, respectively. Subjects consumed significantly more calories during the fructose- and glucose-diet periods compared to the aspartame-diet period (p < 0.001). However, energy intake did not differ to a significant degree between the fructose- and glucose-diet periods (p = 0.462). Four subjects in the fructose-diet period and seven subjects in the glucose-diet period were able to partially compensate for the energy intake from the SSB by reducing their intake of solid food. The degree to which subjects were able to compensate for energy in the SSB did not differ between the fructose- and glucose-diet periods (p = 0.136).

Conclusion: The consumption of SSB placed subjects in a state of increased energy intake as many of them were unable to reduce their intake of solid food to compensate for energy taken up through the SSB. This effect was present in both the fructose and glucose arms, thus suggesting that liquid calories from SSB promote overconsumption of energy independent of the type of sugar used to sweeten the beverage. Our study lacked the power to determine conclusively whether the degree of compensation for liquid calories taken up as fructose differed relative to liquid calories from glucose.