This case, no matter if you are fit or obese, it can only be solved by being organized. (although I have been told that raisins and sultans are good for memory, but could just be an old wives tale)
You need a diary/organiser. Right down all your tasks for the next day before you sleep. And next to the task, right down the most important items you need.

Or if you dont have a diary, phone will do.