Responsible adults usually have to spend quite a lot of time thinking about food.

They need to schedule their meals so that they happen when they (and potentially other people) are hungry, they have to plan what it is that they are going to prepare, and ideally, they must get right that difficult balance of the meal being both reasonably healthy and tasty enough that they will enjoy eating it. Rinse and repeat three times a day, seven days a week. That is a lot of mental and physical energy expended just on what we need to fuel ourselves.