> count your kcal for one month Bingo. When I was much younger I was super skinny. I was weight lifting, but simply not gaining weight. I thought I ate a lot,

> count your kcal for one month Bingo. When I was much younger I was super skinny. I was weight lifting, but simply not gaining weight. I thought I ate a lot, and decided to start tracking. I barely ate anything. Even as a kid I hated to stop doing whatever it was I was doing and taking time to eat. That spilled over into adult life. But, once I saw numbers it became clear and I was finally able to adjust. Humans are generally terrible at estimations like this. I suggest tracking anything that you think may be a negative in your life.