Cheats can be really bad or not so bad, it depends on what you do and what your goals are. If you're doing very low carb fat loss, you're going to be pretty sensitive to carbs so any carb blasts (8 beers and mexi food) are probably going to throw you off. Then for those with auto-immune problems, the shit that sets them off is going to be off-limits. I had eczema, acne, and mood-disorders since I was young. Turns out it's gluten, although I'm not "celiac" according to doctors, I'm sensitive to it according to a naturopath. Same goes for dairy for me. Gluten, dairy, big ol' heaping helpings of oxidized omega 6 or trans fats. That stuff is not good for cheats. A cheat shouldn't derail your progress, and with the GI irritating stuff or the liver-damaging stuff, it can leave consequences that last a while.
I cheat with a couple of shots of Jagermeister and occasionally some chickpeas.
Stabbing conventional wisdom in its face.
Anyone who wants to talk nutrition should PM me!