Intermittent fasting changes the timing of eating. It does not guarantee weight loss, preserve all muscle or produce a fixed amount of daily weight change. The overall eating pattern and individual circumstances matter.
Discuss fasting with a clinician if you take glucose-lowering medication, are pregnant or breastfeeding, have a history of an eating disorder or have a condition that makes missed meals unsafe. Medication changes should never be made without the prescriber.
Adequate nutrition, sufficient protein and appropriate activity matter more than following an extreme schedule. Dizziness, weakness or difficulty meeting nutritional needs are reasons to reconsider the approach.
A sustainable plan can use regular meals instead. Choose an approach that fits clinical needs and can be maintained without shame, excessive restriction or a promised transformation.