Literature
Clinical Pearls & Morning Reports
Published April 20, 2022
How did time-restricted eating with calorie restriction compare with calorie restriction alone in the trial by Liu et al.?
Liu et al. conducted a randomized clinical trial that assessed time-restricted eating (eating only between 8:00 a.m. and 4:00 p.m.) with calorie restriction as compared with daily calorie restriction alone regarding weight loss and metabolic risk factors in obese adults. Read the NEJM Original Article here.
Clinical Pearls
Q: What is time-restricted eating?
A: Time-restricted eating is an intermittent-fasting regimen that involves a shortened period of time for eating within each 24-hour period. The method has gained popularity because it is a weight-loss strategy that is simple to follow, which may enhance adherence. Observational studies have suggested that the practice of eating meals later in the day was associated with weight gain and influenced the success of weight-loss therapy.
Q: What is known about the potential of time-restricted eating as a weight-loss strategy?
A: Several pilot clinical studies showed that time-restricted eating resulted in reduction over time in the body weight and fat mass in patients with obesity. Lowe and colleagues tested the short-term effect of time-restricted eating on weight loss (in which food was eaten only during the period from 12:00 p.m. to 8:00 p.m.) in 116 obese patients. They found that weight loss with time-restricted eating was similar to that with ad libitum calorie intake. However, these studies did not provide information that was sufficiently conclusive to support evidence-based clinical guidelines for obesity. In addition, the long-term efficacy and safety of time-restricted eating as a weight-loss strategy are still uncertain, and the long-term effects on weight loss of time-restricted eating as compared with daily calorie restriction alone have not been fully explored.
Morning Report Questions
Q: How did time-restricted eating with calorie restriction compare with calorie restriction alone regarding weight loss in the trial by Liu et al.?
A: In this 12-month trial, the authors found that the 8-hour time-restricted–eating regimen did not produce greater weight loss than the regimen of daily calorie restriction, with both regimens resulting in similar caloric deficits. The mean weight change from baseline to 12 months was −8.0 kg (95% confidence interval [CI], −9.6 to −6.4) in the time-restricted–eating group and −6.3 kg (95% CI, −7.8 to −4.7) in the daily-calorie-restriction group. There was no significant difference between the two groups in weight change (net difference, −1.8 kg; 95% CI, −4.0 to 0.4; P=0.11). The percentages of participants with a weight loss of more than 5%, 10%, and 15% at 12 months were similar in the two groups.
Q: How did the two groups in the trial by Liu et al. compare regarding improvements in body composition and metabolic risk factors?
A: The body fat mass at 12 months was reduced by 5.9 kg (95% CI, −7.1 to −4.7) from baseline in the time-restricted–eating group and by 4.5 kg (95% CI, −5.6 to −3.3) in the daily-calorie-restriction group, with no substantial differences between the groups. Both the time-restricted–eating and daily-calorie-restriction diets led to loss of lean mass, abdominal visceral fat, subcutaneous fat, and liver fat; there were no differences between the groups. Both time-restricted eating and daily calorie restriction were associated with reduced systolic and diastolic blood pressure over 12 months, with no substantial between-group differences. Fasting glucose levels, 2-hour postprandial glucose levels, scores on the insulin disposition index and HOMA–IR (insulin resistance as assessed using the homeostasis model assessment of insulin resistance), and lipid levels were similar in the two groups during the 12 months of the trial.