Calorie restriction, with or without restricted eating, shows similar effects on weight loss

Daily calorie restriction, regardless of whether or not eating was time-restricted between 8:00 am and 4:00 pm, showed similar effects on weight loss in patients with obesity, according to a recent study.

The researchers conducted a study involving 139 patients (mean age 31.9 years) with obesity (mean body weight 88.2 kg) who were recruited from the general population in China. Participants were randomly assigned to either 8-hour time-restricted eating with daily calorie restriction (n=69) or daily calorie restriction alone (n=70) for 12 months. The calorie-restricted diet was limited to 1,500–1,800 kcal/day for men and 1,200–1,500 kcal/day for women, with 40–55 percent of calories obtained from carbohydrates, 15–20 percent from protein, and 20–30 percent from fat. [N Engl J Med 2022;386:1495-1504]

At 12 months, there was no significant difference in mean body weight loss from baseline between the time-restricted eating group and the daily calorie restriction-alone group (-8.0 vs -6.3 kg; difference between groups, -1.8 kg; p=0.11).

Both the time-restricted eating group and daily calorie restriction-alone group also showed similar reductions in waist circumference (-8.8 vs -7.0 cm), body fat mass (-5.9 vs -4.5 kg), body mass index (-2.9 vs -2.3 kg/m²), and body lean mass (-1.7 vs -1.4 kg).

There were also similar reductions in abdominal visceral fat and subcutaneous fat between the time-restricted eating and daily calorie restriction-alone groups (-26.0 vs -21.2 cm² [abdominal visceral fat] and -53.2 vs -37.0 cm² [abdominal subcutaneous fat]).

The reductions in systolic (-8.1 vs -7.7 mm Hg) and diastolic (-5.1 vs -3.8 mm Hg) blood pressure did not differ between the time-restricted eating and the daily calorie restriction-alone groups.

Both diet groups also showed similar results with regard to other metabolic risk factors, such as glucose and lipid levels.

Adverse event (AE) rates were comparable between both groups, with no deaths or serious AEs reported.

“Weight loss by means of lifestyle modification has been documented to be the cornerstone of weight management [in patients with obesity, which] … is a major global public health challenge. Thus, identification of alternative and feasible dietary interventions for weight loss is a major public health priority,” said the researchers.

“In our trial, we found that the two weight-loss regimens that we evaluated had similar success in patients with obesity, regardless of whether they reduced their calorie consumption through time-restricted eating or through calorie restriction alone,” they said.

“[The] time-restricted eating and daily calorie restriction [regimens also] produced similar effects with respect to reductions in body fat, visceral fat, blood pressure, glucose levels, and lipid levels over the 12-month intervention period,” the researchers noted.

“[O]ur findings suggest that the time-restricted eating regimen worked as an alternative option for weight management,” they added.