Researchers in PLOS ONE suggest that physicians who provide advice on weight management should consider including advice on the 5:2 diet, which may enhance adherence and efficacy.

The 5:2 diet, a type of intermittent energy restriction, limits caloric intake on two non-consecutive days a week (to 500-600 calories) and the remaining days of the week follow “sensible eating but no formal energy restrictions,” according to researchers.

A total of 300 adult participants with a BMI ≥ 30 kg/m2 were randomized to receive Standard Brief Advice (SBA) on diet and physical activity (n = 100); 5:2 self-help instructions (5:2SH) (n = 100); or 5:2SH plus six once-weekly group support sessions (n = 100).

In the group assigned SBA, participants received copies of the British Heart Foundation healthy eating and exercise booklets and a listing of local resources for exercise. An advisor explained the program and reviewed important advice and answered questions.

For the self-help format of the 5:2 diet (5:2SH), participants received a leaflet on restricting caloric intake, the local resources for exercise leaflet, and information about online support for 5:2 dieters. An advisor also explained the program and answered questions. 

In the group support format (5:2G), participants received the 5:2SH intervention and an invitation to six 1-hour group sessions. They discussed their experience over the week and adherence to the plan. Use of a 5:2 internet forum was also encouraged.

“The 5:2 diet does not require relentless self-control and allows dieters to stop worrying about food intake” for most of the week, Peter Hajek, Queen Mary University of London, and researchers wrote.

Initial adherence to 5:2SH was high but it declined over time from 74% at 6 weeks to 31% at 6 months and 22% at one year.
The ratings for 5:2SH were significantly higher and that intervention had no negative effect on fat and fiber intake and physical activity, when compared to SBA.

Similar weight loss resulted from 5:2SH and SBA at six months (-1.8 kg vs. -1.7kg) and at one year (-1.9kg vs. -1.8kg). In the 5:2SH group, 18% of participants lost ≥ 5% of their body weight compared to 15% in SBA at one year.

5:2G resulted in greater weight loss at 6 weeks (-2.3kg vs. -1.5kg) but by one year, the difference was no longer significant, according to researchers.

The results can be interpreted in two ways, according to Hajek and colleagues.

“One is that the results are only modest, and so neither intervention is worthwhile. However, it is also possible to argue that the one-year weight loss of at least 5% of the baseline body weight in 15%-18% of participants is not negligible; and that the 5:2 advice, which received more favorable user ratings, is also much simpler and easier to deliver than multimodal briefing on several complex lifestyle changes,” according to Peter Hajek, Health and Lifestyle Research Unit, Wolfson Institute of Population Health, Queen Mary University of London, and colleagues.


Reference:
Hajek P, et al. PLOS ONE. https://doi.org/10.1371/journal.pone.0258853. Nov 17, 2021.

Disclosures: No authors declared financial ties to drugmakers.
Images: Getty Images, Pixabay

By MD /alert Staff