Intermittent fasting is not appropriate for everyone, and some groups should avoid it or discuss it with a clinician before starting.

This page isolates one claim from the wider argument of The Human OS Manual.

The classification describes the evidence supporting this claim, not the Human OS framework as a whole.

Johns Hopkins Medicine advises medical discussion before starting intermittent fasting and specifically advises against it for children and teens under 18, pregnant or breastfeeding women, people with type 1 diabetes who take insulin, and people with a history of eating disorders. It also warns that prolonged fasts are not necessarily better and may be dangerous.

This guidance is not a comprehensive contraindication standard for every disease, medication, age group, athletic context, or fasting protocol.

This is clinical guidance rather than a graded systematic review of all fasting contraindications. It is presented as safety context, not an evidence-strength claim about efficacy.

Sources are listed according to the role they play in this claim. One source may provide direct support, another may explain a mechanism, establish a limitation, or prevent an interpretation from becoming broader than the evidence allows.

The printed book preserves the claim inside the argument that gives it meaning. These references connect the current digital record to the first-edition evidence trail.

This claim connects to the following parts of the Human OS architecture. The module labels locate the claim inside the framework; they do not imply that the research source validates the architecture itself.

This section identifies practical boundaries relevant to the claim. It does not provide individualized medical guidance.