The thing is, exercise still reduces appetite. It raises the blood sugar levels as the body supplies the muscles with carbohydrates, and triggers a complementary response in appetite hormones. Finally, and most importantly: Exercise releases dopamine. Dieting is universally a mood killer, because kilo-joule deficit equals starvation. So whilst it does not directly impact weight loss. It still makes it (a bit) easier.…
I practice intermittent fasting a lot and I cannot say that it affects my mood negatively. But I was very grumpy when I ate "five small meals a day".
It seems that the digestive system is more OK with being totally empty than being just half full all the time.