Tag: Fasting and muscle loss

According to research published in *The Lancet*, during controlled fasting interventions, subjects lost minimal functional muscle mass that was quickly regained upon refeeding. The question of whether fasting makes you burn muscle is a common concern for those exploring this dietary strategy for weight loss and metabolic health.

According to a 2025 study in the journal *Impact of Long-Term Fasting on Skeletal Muscle*, minimal actual muscle loss was observed after 12 days of fasting when accounting for water and glycogen depletion, despite significant weight loss. This challenges the long-held myth that you automatically lose muscle during fasting, and helps answer the question, "What's the longest I can fast without losing muscle?".

According to a study published by the National Institutes of Health, after an initial period of protein loss, fasting triggers a protein-sparing phase as the body shifts toward fat metabolism. This reveals a critical nuance to the question: Will I lose a lot of muscle if I go on a fast? The answer depends heavily on the type and duration of your fast, and how you support your body.