not even just different groceries, but doing something different with the same stuff. For example, ill eat chicken like 3 times a week, sometimes i barbeque it, sometimes i make fajiitaas with onions and green pepper, sometimes i make gumbo/jumboliya.
Or eggs for that matter, plain old eggs get boring, add some mushrooms, onions, peppers... yummy stuff thats healthy..
About sweet potatoes, not only are they great for you, but i prefer the taste of them to regular 100x, they are seriously fuckin awsome.
same with oatmeal, you can add so many different fruits and nuts, a little cinammon and brown sugar...
Search for a good chili recipe, chili is awsome and keeps you fed for days
Fish of any sort is sweet and you can prepare it so many ways..
+1 to whomever mentioned salmon bugers, they taste really good and are healthy and relatively inexpensive.