I never really found the eating more when exercising more that compelling personally. I mainly meal prep and eat the same amount whether or not I work out and how hard I work out.

I feel like saying that someone is going to eat more because they are start exercising a lot is a separate topic. But I would think that someone who has the willpower to start exercising drastically more also has the willpower to control what they physically put in their mouth. I have personally found that stopping putting things in my mouth to eat is easier than getting myself to exercise as much as I would like to, so I don't think it's a guarantee that someone choosing to exercise more will automatically eat more.