One-year ad libitum consumption of diacylglycerol oil as part of a regular diet results in modest weight loss in comparison with consumption of a triacylglycerol control oil in overweight Japanese subjects.

OBJECTIVE: The objective of this study was to investigate the effect of 1-year ad libitum consumption of diacylglycerol oil on body weight and serum triglyceride in Japanese men and women. DESIGN/SUBJECTS/INTERVENTION: In a 1-year double-blind, placebo-controlled parallel trial with clinic visits at month 0, 3, 6, 9, and 12, a total of 312 Japanese men (n=174) and women (n=138) (aged 22 to 73 years) with body mass index (calculated as kg/m(2)) > or =25 and/or fasting serum triglyceride level > or =150 mg/dL (1.70 mmol/L) (aged 22 to 73 years) were randomly assigned to the diacylglycerol (n=155) or triacylglycerol (n=157) group. Participants substituted their usual home cooking oil with the assigned test oils. MAIN OUTCOME MEASURES: Changes in anthropometrics and serum triglyceride level were monitored at 3-month intervals across a 12-month period. RESULTS: In the intention-to-treat analysis, body weight decreased significantly in the diacylglycerol group when compared to the triacylglycerol group (P=0.013). Changes in body weight and body mass index during the study period differed between the two groups by 0.87 kg (P=0.002) and 0.32 kg (P=0.002), respectively. Participants with higher initial body mass index or greater percentage of total fat intake as diacylglycerol exhibited greater reduction in body weight. Total energy intake and physical activity were not significantly different between the groups during the study. Serum triglyceride levels decreased significantly from values in individuals with hypertriglyceridemia, but did not differ between groups. CONCLUSIONS: Modest body weight reduction was observed after 1-year ad libitum consumption of diacylglycerol oil as part of a regular diet in comparison to that of triacylglycerol oil; weight loss was greatest in participants who were obese at baseline. The weight reduction observed in diacylglycerol group was attributed to the substitution of usual home cooking oil with diacylglycerol, because total energy intake and physical activity did not differ between groups.