Very-low-calorie ketogenic diets were linked to mixed gut microbiome changes
A review in people with obesity found higher microbial diversity, increased relative abundance of Akkermansia and reduced relative abundance of Bifidobacterium. Health benefits remain unestablished.
Based on the published abstract. The full paper may contain additional methods, results and limitations.
The 30-second takeaway
The pooled studies reported greater microbial diversity, a larger relative share of Akkermansia and a smaller relative share of Bifidobacterium with very-low-calorie ketogenic diets. The Firmicutes-to-Bacteroidetes ratio also increased, a separate finding. These microbiome measurements do not establish better symptoms or lower disease risk, and their overall health meaning remains unclear in the abstract.
The abstract does not specify comparison conditions or overall intervention durations. It reports microbial measurements without demonstrating patient health benefits, and the authors call for further study of long-term safety.
Shares, diversity and ratios
Relative abundance describes a bacterial group’s share of the microbial community, not its absolute quantity. Diversity indices measure another aspect of that community. A higher Firmicutes-to-Bacteroidetes ratio does not show that both bacterial groups increased.
Subgroups leave practical questions
The researchers explored variation by age, body mass index and intervention length. Those subgroup patterns do not establish who should follow the diet or for how long, nor whether the microbial shifts produce lasting health benefits.
The original publication
The impact of very-low-calorie ketogenic diets on gut microbiota in individuals with obesity: a systematic review and meta-analysis.
Wang S, Bao Z, Li Z et al.
Gut Microbes · 2025
- PubMed ID
- 41054273
- Record checked
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