Time-restricted dieting is no better than daily calorie restriction alone for weight loss or reducing metabolic risk factors in patients with obesity, a small trial shows.

The findings suggest that although limiting food consumption to an eight-hour window each day is still effective, the Chinese researchers say the benefits seen with this approach are primarily driven by caloric deficits.

Writing in the New England Journal of Medicine, the team report assigning 139 adults in Guangzhou, China to time-restricted eating (8am to 4pm) with calorie restriction or daily calorie restriction alone to determine the long-term efficacy and safety of the former approach.

The average age and BMI were 32 years and 32kg/m²; all participants were encouraged to restrict their caloric intake to 1500-1800kcal/day in men and 1200-1500kcal/day in women.