I've "discovered" it long time ago. Basically if I feel hungry but do some activity instead of eating the hunger disappears. Does not work on long cardio activi

I've "discovered" it long time ago. Basically if I feel hungry but do some activity instead of eating the hunger disappears. Does not work on long cardio activity though. Anything longer than 2-3 hours (assuming it is not a leisure walk) exhausts my reserves and makes me hungry for real.