I think so, but I never really measured the actual amounts I eat, and what, in both cases. It also heavily depends on what you're doing when sitting still: using your brain actively for work for instance is going to require quite some energy in comparison with just sitting still and relaxing. AFAIK the brain's main energy source is sugar so my (completely unverified - it's hard these days to find the truth amongst the insane amount of dietary bs out there) assumption is that physical exertion needs / can use different metabolic pathways not requiring instant sugar intake.

Something related happens to me as well, during light physical exertion: even when I get hungry, I can just keep on going and after like 30 minutes I don't feel the hunger anymore, and can keep on going for a couple of hours more. That just doesn't work for me when programming/debugging: then I keep on being hungry and after a while just cannot think properly anymore (could be placebo/confirmation bias, unsure.)