Cooking, storing for long periods of time and (I think) drying all degrade Vitamin C, so don't forget the fresh fruit topping if you're planning on living off of oatmeal!

You need a big bowl if you want enough calories to make it worth the effort. 1/2 cup oats is only about 40g, so you'd need 13 servings to meet the standard 2000kcal daily requirement (which is too low for anybody who exercises regularly).

I think 100g is a more realistic serving size, and that will spill and make a big mess if you try cooking it in a normal breakfast cereal bowl. I have a bowl about twice that size and I still cover the bowl with plastic wrap to avoid spilling any.