Depending on the length of the cutting diet, yes cheat days are definately necessary. They keep you mentally focused by giving you something to shoot for. Since you are planning your cheat day/meals you are less likely to go off your diet randomly and gorge yourself on shitty foods. cheat days (or in many instances carb up days) restore muscle glycogen also, this is important if you dont want to lose muscle mass.

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I don't do this for my family, my friends, women, accolades, pride, or ego. I do it for me and no one else, its just part of who I am.