I'm on a primal/paleo/whatever diet and eat a ton of eggs and apples. I eat a lot of other stuff, too, but eggs and apples work great for me, are healthy, and are dirt cheap. I'm over 40, and carry absolutely zero extra weight.
My wife is Korean and often will make a simple soup like seaweed, kimchi, or radish and will have it with brown rice. Very healthy and super inexpensive.
Paleo/primal diet is great. Basically eating healthy food :-).