Have you ever wondered why people who follow diets they see in the magazine,social media, T.V loose weight for a short period of time then gain it back? well it's because most people cannot maintain those type of diets.
If you want to loose weight and keep it of you have to find something that works for you and you can maintain for a long period of time all this 2 week diet plan or 3 week diet plan is going to hurt you.
If you want to improve your fitness you have to think longterm. Think of the longterm benefits. Don't just loose weight because you want to fit into that wedding dress or you want to fit into that jeans, that is short term thinking.
You will never win if you continue to think like that