... and speaking of nutrition and protein ...
Whey powder is an excellent source. If you get the kind with the natural vanilla, it will taste ... less bad at first, and good later. My husband's first homemade shakes included dairy or soy milk, whey powder, 1 or 2 packages of breakfast essentials, and canned peaches. Once these were going down well, I picked up toddler oatmeal cereal and that went in the shakes: its smooth and mixes up easilly, and has some 'stick to your ribs' quality. If you can do one of these for breakfast, you can bring a pack of nutrition drinks (get the high protein kind) to work with you for lunch and breaks.

Oh - and very important, have a water bottle or three or four.