Easy, I eat all kind of junk and fast foods, barely do any sports and usually about once a year I get an unrelated health problem and need to do a surgery that make my body go through a difficult time and all that make me lose weight.Im at around 6 surgeries since 2020.You'd think my body would suffer from it but boy haven't you seen my mental state since.
But I know that we all don't have the chance of having a body that is disintegrating itself,so when I was younger what worked for me was eat whatever I want but never take elevator and do your groceries by foot, I lost weight and gained quite some muscles.