Research
Adherence
Adding weekly group support to the 5:2 diet improves short-term adherence and weight loss (at 6 weeks), but this advantage diminishes and becomes statistically non-significant by 12 months.
If you start the 5:2 diet, try to get some form of support for the first 6 weeks, such as a group session or a buddy system. This will help you lose more weight initially. However, be aware that this advantage may fade after a year, so focus on building sustainable habits rather than relying solely on support.
GoodQualifiesMEDIUM confidence
Compared to 5:2SH, 5:2G generated a greater weight loss at 6 weeks (-2.3kg vs -1.5kg; b = 0.74, 95%CI:1.37–0.11, p = 0.02), but by one year, the difference was no longer significant (-2.6kg vs -1.9kg, p = 0.37; ≥5% body weight loss 28% vs 18%, p = 0.10).
Why this rating
RCT data shows clear short-term benefit but lack of long-term significance.
Source
A randomised controlled trial of the 5:2 diet
Peter Hájek et al. · PLoS ONE · 2021
DOI 10.1371/journal.pone.0258853
rct · n=300Cited 34×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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