Article Impact Level: HIGH Data Quality: STRONG Summary of Annals of Internal Medicine, ANNALS-24-01631. https://doi.org/10.7326/ANNALS-24-01631 Dr. Victoria A. Catenacci et al.
Points
- This study compared intermittent fasting and daily caloric restriction over 12 months to evaluate their effects on weight loss within a behavioral program that included dietary guidance and physical activity recommendations.
- Participants practicing 4:3 intermittent fasting lost significantly more weight than those following daily restriction, with an average difference of 2.89 kilograms favoring the intermittent fasting group at the 12-month mark.
- Both groups followed a matched weekly calorie deficit and received high-intensity behavioral support, but intermittent fasting produced modestly more significant weight loss while maintaining similar adherence and completion rates.
- The study involved 165 adults with elevated BMI, and 125 completed the trial, demonstrating that intermittent fasting can be a practical alternative in structured weight loss interventions.
- While the results are promising, the researchers note that broader studies are needed to assess whether intermittent fasting is equally effective across more diverse populations and long-term settings.
Summary
This study compared the effects of intermittent fasting (IMF) and daily caloric restriction (DCR) on weight loss after 12 months within a comprehensive behavioral weight loss program. The trial randomized 165 adults aged 18 to 60 with a body mass index (BMI) of 27 to 46 kg/m² to one of two groups: 4:3 IMF or DCR. Participants in the IMF group restricted caloric intake by 80% on three nonconsecutive days each week, while the DCR group reduced daily intake by 34% to match the weekly energy deficit of the IMF group. Both groups received high-intensity behavioral support and were encouraged to engage in 300 minutes of moderate-intensity physical activity weekly. The primary outcome was the change in body weight at 12 months.
At 12 months, the 4:3 IMF group demonstrated a more significant weight loss than the DCR group. Specifically, the 4:3 IMF group experienced a mean weight loss of 2.89 kg (95% CI, −5.65 to −0.14 kg; P = 0.040), which was statistically significant. Of the 165 participants, 125 completed the trial, with 84 in the 4:3 IMF group and 81 in the DCR group. The analysis showed that despite both interventions being effective, IMF resulted in modestly more significant weight loss than DCR.
The findings suggest that, in the context of a comprehensive behavioral weight loss program, the 4:3 IMF approach may offer a viable alternative to daily caloric restriction for weight management in individuals with overweight or obesity—however, the study’s limited generalizability warrants further investigation to confirm these results in broader populations.
Link to the article: https://www.acpjournals.org/doi/10.7326/ANNALS-24-01631
References Catenacci, V. A., Ostendorf, D. M., Pan, Z., Kaizer, L. K., Creasy, S. A., Zaman, A., Caldwell, A. E., Dahle, J., Swanson, B., Breit, M. J., Bing, K., Wayland, L. T., Panter, S. L., Scorsone, J. J., Bessesen, D. H., MacLean, P., & Melanson, E. L. (2025). The effect of 4:3 intermittent fasting on weight loss at 12 months: A randomized clinical trial. Annals of Internal Medicine, ANNALS-24-01631. https://doi.org/10.7326/ANNALS-24-01631
