Oats certainly do spike blood sugar, all carbohydrates spike blood sugar and to recommend oatmeal for diabetics is ludicrous. Oats are 80% carbohydrate, they contain more carbohydrates than potatoes and rice.
I have to pitch in with the "beans and rice" brigade here. There is a very good reason it is so well known as a combination: it is cheap, filling and nutritious. Although you probably should not live solely on it, it will surely take you a long way. So long as you have plenty of fruit and vegetables too (both fairly easy to obtain cheaply, particularly at local markets), you do not really need a lot else. The only reason you might get anything else would simply be for variety but there are plenty of variations you can make to rice and beans to change it quite significantly. With some herbs and spices, it becomes the "Swiss army knife" of food!
