Visit your local farmer's market. Buy more fruits and vegetables than you think you could ever eat. During the day, when hungry, ingest fruit and / or vegetable as needed to extinguish hunger.
For dinner, reward yourself with whatever other garbage you would have had instead.
Obviously, hence the "whatever crap" comment. Most of the things we eat in a hurry have plenty of fat, protein and calories, but not nearly enough of the things we ought to be getting from fruits and vegetables.
I'm not suggesting that somebody try to survive _only_ by eating fruits and vegetables. I was suggesting eating them during the day when people would otherwise be eating potato chips and soda.
Speaking of ... as far as sugar overload is concerned, you'd have to eat three or four apples to match the sugar in a single can of cola, which has basically no nutritional value whatsoever.
In the spirit of this thread, they have zero preparation time, are easily accessible (keep them in a desk drawer, or on the desk), and have a lot of nutrients our bodies need. If you get high quality produce, it's also quite delicious.
Okay, fruit and veggies for snacking. That's good advice -- I thought you were suggesting that someone should eat that instead of daytime meals. Clearly I was mistaken. :)
I'd also add beans and some seeds which can be used as grains (assuming you are going veg).
Amaranth, Quinoa and spelt. Have more protein than most meats.
The sugar than you talk about is good for you. The problem is with refined sugar, which creates unusual changes in blood sugar which causes dips and highs.
So fruit and veg are good. I would wash them properly, as non organic stuff is full of pesticides and please look past the way the food looks, care about the way it tastes.
For dinner, reward yourself with whatever other garbage you would have had instead.