In the fitness industry this topic is HIGHLY debated and like most other things is something that varies for goals and each person. Let's look at both sides of the story...
To cheat: these individuals believe that there are 2 prime reasons to cheat:
1~ mental effects-- many people who are eating healthy are unfortunately "depriving themselves" of the foods that the industry has trained us to crave. So rather than full out binging you allow yourself one controlled "naughty food" that will keep you satisfied and on track.
2~physical-- other individuals believe cheat meals rebuild your glycogen stores which they say that dieting or eating clean for an extended amount of time ultimately depletes, making it harder for you to work out at 100% intensity.
Other individuals believe that your body runs like a car with fuel. If you put regular gasoline in a car that requires premium your body, like that car, will run sluggish and not function how it should. And you can also potentially ruin the internal workings of that car as well.
No this is not me but this sure is my biggest weakness! I do get cravings, I do want to eat crappy when stressed (mostly because it's more convenient) BUT I can recognize these triggers and no longer worry as much. PRACTICE MAKES PERFECT!
Also, I no longer feel deprived NOT eating those foods because I know how bad they are for my body and my goals! I do most definitely indulge from time to time.
What works for me is balancing everything. If I want something crappy I usually try to figure out why first. Is it hunger? Is it thirst? Is it stress/sleep deprivation?
If I really feel like I NEED something I will have it because I know I will just go back later and eat 2x as bad! I don't usually plan a cheat but if it happens it happens. My rule? 80% of my week is clean eating and if I fudge a little it's alright because no one is perfect. Also, I know even if I want that cheat food, I always feel bad (almost always) afterwards so most times it isn't worth it!
My favorite cheats: Pizza, cakes, bread, pretzels and french fries. What an odd mix?