This is quite a prevalent and important topic to touch on in my experience, as it's probably one of the most if not the most asked question I get asked.
Obviously there are differing opinions on this, but I'd like to share my approach and what has worked for me and my clients.
I don't like referring to the term "cheat" meal but a rather an off plan meal as I feel most people take the term cheat meal as a free for all, balls to the wall, thumbs up to just eat whatever the fuck they want, for how long they want or till they can't stomach anything further. My opinion, whether your goal is to add quality size and the exclamation on the word quality or to lean down, doing the above will hamper your progress. If the goal is to add quality size, you will store unwanted fat, you'll think your gaining lean tissue when in actual fact you are getting fat. On the other hand when you are trying to lean out, you need to be in a weekly calorie deficit to attain that result. If your off plan meal isn't structured that deficit will be much smaller than it should be or as designed by yourself or your coach.
With regards to the off plan meal the most important factor is your actual calorie intake and not so much the macros of that meal. Keep this in mind.
So my approach as well as that of many coaches I follow and have had the privilege to work with or consult is pretty simple.
Daily Calorie Intake = 3000 calories split between 6 meals
Weekly Calorie Intake = 21000 calories
You plan to take your off plan meal on a Saturday to spend quality time with your family, and would like to take them for dinner.
Saturday (Which is a training day) :
You remove meal 5 and 6 which consists of let's say 1000 calories
You have a meal and a desert that consists of let's call it 1800 calories, which means you are 800 calories in a surplus. 1800-1000 = 800 calories
Sunday (Non training day) :
You remove your pre workout which is 450 calories.
Your intra workout has 40g of fast digesting carbs which are another 160 calories.
You are now in a surplus of 800-610 = 190 calories
The above is sort of the maximum I'd recommend going over your weekly calorie intake, regardless of the goal. This is a nice way to ensure your mind stays at ease with some good food AND to ensure that your progress isn't hampered!
Use it, don't use.
Yours in fitness