Cheat meals can counteract all your hard work during the week. If you want a little treat; have it and move on. Moderation is key! Try to limit your treats to 1x/week.
Does eating healthy mean you can never have your favourite things again? Absolutely not! There is a difference in having a slice or eating a whole cake. If you want pizza, have a slice and move on. If you know you are going out for pizza one evening, focus on getting extra veggies and protein earlier during the day and leave some extra carbs for your pizza. MyFitnessPal is a great way to track your intake and still be able to fit in a treat while staying on track! Log your treat in at the beginning of the day and work the rest of your intake around what macro-nutrients you have left for the day.
Drink lots of water and exercise. Remember, moderation is key. If you really want something, have a little piece then move on and get back to the plan.