Also, before I learned to cook, I used to eat microwavable ready meals (which are really pretty good in the UK). I'd boil some pre-chopped* veg to go with them for vitamins etc. I also made sure I ate plenty of fruit.

*In the UK, a lot of supermarkets will sell already chopped vegetables at a slightly higher price. Buying them can improve your life (and save time) if you don't like chopping vegetables!