RefeedDiet break · Refeed day

A refeed is a planned short period of higher calorie intake during a diet, usually one or two days, with the extra calories coming mostly from carbohydrate. It is distinct from a cheat day, which is unstructured, and from a diet break, which lasts a week or more at maintenance.

The proposed rationale involves several mechanisms: restoring muscle glycogen, temporarily raising leptin, and providing a psychological break. The physiological case is weaker than the marketing, since leptin rises quickly and falls again almost as fast, and one or two days is unlikely to reverse metabolic adaptation meaningfully.

The stronger case is behavioural and performance related. Training quality often improves after refilling glycogen, and a planned high carbohydrate day can make a long diet more tolerable and reduce the chances of an unplanned week of it.

The trap is arithmetic. A refeed only works if it is planned and counted; a day of eating whatever appears can easily erase most of a week's deficit, particularly late in a diet when the weekly deficit is modest.

The scale will rise afterwards, sometimes sharply, because glycogen carries roughly three grams of water per gram. That is not fat gain and it resolves within a few days, but it catches people out badly if they were not expecting it.

For a longer diet, a structured week at maintenance every so often has better evidence behind it than single refeed days.

In practice, if you use them, plan the calories, take them mostly from carbohydrate, place them before hard sessions, and expect a temporary bump on the scale.