Also note that while losing weight is simply calories in > calories out, in the long term there are some factors that can make a difference. First off the longer you spend starving yourself your body will start to slow your metabolism down. Your body wants to keep its fat, it makes you fitter for survival in lean times. So simply starving yourself typically isnt as efficient as doing things like intermittent fasting. Again this doesnt mean that one is better for this person or that person, but just mathematically you can lose more weight that way.

Also remember that even if you are intaking less calories, you still need certain nutrients to be healthy. Your body requires fats, carbohydrates and proteins, as well as nutrients and vitamins to survive.

Unless you are very skilled and knowledgeable about balancing diets and meeting all these requirements and such, cheat days are a benefit to your overall health. Your body will often crave things it needs, so every now and then, you should treat yourself.