Gaining

Get a snack you would normally eat during a movie. Usually those are pretty easy to just mindlessly eat. Then just kinda eat while you work.

Things that don't make your hands sticky, and don't drop crumbs (don't want to have to go clean after each snack)

Things that you can have sitting out with you (don't need to keep them chilled)

Some variety (you can tired of any one thing)

Both food and drink (sometimes you want one, sometimes another)

For example some chocolate broken into chunks, some easy fruit (bananas, apples), some baked good that is clean (like crackers, non-crumbly cookies, or pretzels), and at the least some water but it you prefer maybe something like sweet ice tea or apple juice.