To be clear: I only mentioned that marathon because it was a particularly clear case of the effect exercise seems to have on my appetite, and I am not recommending it as an exercise regimen.

And while it is not for most people (and definitely not me), there are people I know who thrive on running marathons and the training for it, while otherwise living perfectly normal lives. There is a hypothesis that cursorial / persistence / endurance hunting was a a stage in our ancestors' evolution, and that we have inherited some of the traits of that lifestyle.

https://en.wikipedia.org/wiki/Endurance_running_hypothesis