One of the reasons diets fail, is because you try to fit yourself into someones mold and idea of how you should eat. The best approach is to learn your own energy needs, hunger patterns, preferences, balance of nutrients etc.
Food is something that has to be consumed at a minimum 3 times per day. That is a lot to think about. And, Calories in and calories out sounds very simple in theory but putting it into practice involves several other steps.
If you are consuming less then your body needs to function (less than your resting metabolism rate) you can be causing your body to go into starvation mode.
You could be consuming a healthy amount of calories but not have a balance of protein, fat and carbohydrate. This will still keep you from healthy goals.
Having someone to hold you accountable and motivate you will assist you in meeting your healthy goals. I often hear, I know how to eat healthy. I’m just not doing it. Find a registered dietitian to help put food into your life versus fitting you into someones mold!