d-Allulose enhances postprandial fat oxidation in healthy humans

d-Allulose, a C-3 epimer of d-fructose, has been reported to decrease body weight and adipose tissue weight in animal studies and is expected to be a potent antiobese sweetener. Our animal study suggested that one of the mechanisms of d-allulose's antiobesity function is an increase in energy expenditure. However, a few studies have thus far explored the underlying mechanism in humans. The aim of this study was to examine the effects of a single ingestion of d-allulose on postprandial energy metabolism in healthy participants. Thirteen healthy men and women (mean age of 35.7 ± 2.1 y and body mass index 20.9 ± 0.7 kg/m2) were studied. The study was a randomized, single-blind crossover design with a 1-wk washout period. At 30 min after taking 5 g of d-allulose or 10 mg of aspartame without any sugar as a control, overnight-fasted participants ingested a standardized meal, and energy metabolism was evaluated by a breath-by-breath method. During the experiment, blood was collected and biochemical parameters such as plasma glucose were analyzed. In the d-allulose–treated group, the area under the curve of fat oxidation was significantly higher than in the control group (10.5 ± 0.4 versus 9.6 ± 0.3 kJ·4 h·kg−1 body weight [BW]; P