The Claim

Among individuals following ketogenic diets across diverse health conditions and age groups, 43% experienced at least one adverse event, with gastrointestinal symptoms occurring in 40% of cases and constipation being the most frequent individual adverse event at 24% of all reported events.

Source: Adverse events and tolerability of ketogenic diets – a systematic literature analysis

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
28score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Description
1 study reviewed
In plain English

In people following ketogenic diets, 43% experienced at least one side effect, with 40% having gastrointestinal symptoms and 24% specifically experiencing constipation.

See the scientific wording

Among individuals following ketogenic diets across diverse health conditions and age groups, at least one adverse event was documented in 43% of participants, with gastrointestinal symptoms occurring in 40% of cases and constipation being the most frequent individual adverse event at 24% of all reported events, indicating that mild, transient side effects are common during ketogenic diet adherence.

Why this might work

When someone eats very little fiber and mostly fat and protein, the gut moves slower because there's not enough bulk to push things along. This makes stool hard and dry, leading to constipation. The lack of fiber also changes the gut bacteria, which can cause bloating, discomfort, and other stomach problems.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: Adverse events and tolerability of ketogenic diets – a systematic literature analysis

    This study found that about 4 out of 10 people on keto diets had at least one side effect, with stomach problems like constipation being the most common — just like the claim says.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.