I tried to make some diet, but it seems like diet doesn't want me.

Just kidding, but it's hard to diet especially if you know that the foods that you're eating are delicious.
As for exercise, I did try it a few years ago where I downloaded the app, followed the following exercises for 30 days, and nothing changed to me. As of this moment, I'm trying to do some jumping rope exercises, and I'm making a bit of a progress. Exercise works for me, but if you want to have better results, changing your diet to a more nutritious one would be better. Unfortunately, that isn't the case for me.
