A refeed day — a planned day of higher calorie intake during an otherwise sustained deficit — sounds counterintuitive, but it serves a real purpose for some members on longer diets.
It's psychological as much as physiological
A scheduled break from restriction can meaningfully improve adherence to the diet overall, by giving a member something to look forward to rather than an indefinite restriction.
It's planned, not just 'a cheat day'
The difference between a useful refeed and an unplanned binge is the word planned — a refeed fits into the week's overall structure rather than derailing it.