Let's talk about refeed days/meals-
First and foremost, what is a refeed day? Refeed days are days when you're in a cutting or shredding phase (with the intent to lose body fat), where you incorporate more carbs into your diet than normal.
Why is this important? First and foremost you should know that your body (and brain) run on glucose. When you consume carbohydrates, it's gets broken down into glucose in it's most simple form. Thus, carbs are very very important for performance.
When dieting down to low body fat, protein and fats typically stay the same, but carbs are the macronutrient that gets manipulated overtime. However, after a period of time of being on a strict, lower to moderate carbohydrate diet, the body can become very worn out from the lack of carbs.
Thus, adding in a higher carbohydrate, refeed day is necessary. You can either add these in every certain amount of days or feel them out and utilize them whenever you need them.