Advocating for strict restrictive diets has never been what I am about. I do appreciate that dieting has its place, especially for people whose weight has become a health problem, or to be used on a short-term basis (such as 6 weeks) to help boost results. However, I personally prefer to promote a healthy balanced diet, coupled with regular exercises, as the healthiest and most sustainable way of achieving and maintaining the healthiest version of yourself.
Most strict weight loss diets restrict the types of food you can eat, as well as the number of calories you can consume, in order to create an energy deficit. The less energy you supply your body with, the more likely it is that you will need to tap into your fat stores! Your body is quite smart, though, and will soon adjust to the new diet so that is no longer has to eat away at your energy stores quite so rapidly.
This is where your treat comes into it. (I prefer to call them treats, not cheats and here is why). If you enjoy a treat meal every now and then, you break the pattern your body has become used to and once again it starts to burn through calories at the rate it had done before. So by enjoying a a treat meal once or twice a week, whilst being very aware of your diet the rest of the time, you are actually helping your body stay as efficient as possible at burning through fat stores!
Also, I believe that a little enjoyment every now and then is good for the soul. Even though it is best not to do it all the time, enjoying a treat you love on the odd occasion is good for your emotional health too!