Gaming should be better than most activities involving sitting down and staring at a screen for hours. It's more fun than work, and usually less stressful too.
Plenty of people have managed to bulk up while also doing very mentally challenging jobs. There's nothing to worry about in that respect.
"Thanks to the combination of meat, calcium-rich leaf foods, and a vigorous life, the early hunter-gatherers were robust, with strong skeletons, jaws, and teeth." - Harold McGee, On Food And Cooking: The Science and Lore of the Kitchen