Participants favor 5:2 diet over traditional weight loss advice

Both the 5:2 diet and standard weight management advice were associated with modest weight loss results, but the 5:2 diet received significantly higher ratings among participants, according to findings published in PLoS One.

Researchers said the 5:2 diet involves restricting calories for 2 nonconsecutive days and then eating reasonably for the remainder of the week. On fasting days, the caloric allowance is based on an estimated 25% of mean caloric intake of around 2,000 calories per day for women and 2,400 for men.

“We found that although the 5:2 diet wasn’t superior to traditional approaches in terms of weight loss, users preferred this approach as it was simpler and more attractive,” Katie Myers Smith, BSc, MSc, CPsychol, a Chartered Health psychologist and senior research fellow at Queen Mary University of London, said in a press release.

Myers Smith and colleagues conducted a randomized clinical trial on the long-term effects of the 5:2 diet compared with traditional weight loss advice. They enrolled 300 adults in the U.K. with a BMI of 30 kg/m² or more and those with a BMI of at least 28 kg/m² and comorbidities.

The participants were randomly assigned to one of three interventions: standard brief advice (SBA), in which participants received booklets on exercise and received diet tips from an advisor; a self-help format of the 5:2 diet (5:2SH), in which participants received similar booklets with 5:2 diet information and asked an advisor questions about the method; or a group-support format of the 5:2 diet (5:2G), in which participants received the 5:2SH intervention in addition to attending weekly group support sessions during the first 6 weeks. The researchers followed the participants’ progress for 1 year.

The 5:2SH cohort initially had 74% adherence at week 6. However, adherence declined to 31% at 6 months and 22% at 1 year, according to the researchers. Both the 5:2SH and SBA cohorts achieved similar weight loss at 6 months (–1.8 kg vs. –1.7 kg; 95% CI, –0.79 to 1.27) and 1 year (–1.9 kg vs. –1.8 kg; 95% CI, –1.21 to 1.60). Also, 18% and 15% of participants in these cohorts lost 5% or more of their body weight after 1 year (RR = 0.83; 95% CI, 0.44-1.54).

Myers Smith and colleagues reported that the 5:2SH intervention received significantly higher ratings than SBA. Although both were rated positively by participants, individuals reported a higher likelihood of recommending the 5:2 diet to others. Moreover, participants in the SBA cohort were more likely to report using alternative weight loss treatments.

Individuals in the 5:2G cohort reported significant reductions in hunger ratings after the initial few weeks, according to the researchers. This cohort also achieved greater weight loss at 6 weeks compared with the 5:2SH group (–2.3 kg vs. –1.5 kg; 95% CI, 1.37-0.11). However, the differences between the interventions were no longer significant at 1 year.

“Clinicians providing brief advice on weight management may consider recommending the 5:2 diet,” Myers Smith and colleagues wrote.

References:

Brief 5:2 diet advice is as effective as traditional GP advice, but people like it better. https://www.qmul.ac.uk/media/news/2021/smd/brief-52-diet-advice-is-as-effective-as-traditional-gp-advice-but-people-like-it-better.html. Published Nov. 17, 2021. Accessed Nov. 18, 2021.

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0258853.