Diet changer here, the first rule of diet, before you even look at what you eat, is that you need to eat. I started eating breakfast consistently. Often eating filling food like leftovers.
I don't think this is necessarily true. For me, eating anything makes me slightly feel worse, either it's feeling a little tired or something else. That's why sometimes, I eat 2 meals a day and get all my calories (~3000 calories) in two meals.
And I feel at my best when I eat at most once a day (with regular fast days). When I eat all day I feel gross and sluggish.