Crusts

In an attempt to not waste food, my grandpa used to tell me that eating my crusts would make my hair shiny (I usually preferred to go without shiny hair). I've never known a child who did like to eat the crusts of a sandwich.

I'm all about not wasting food (now that I'm a responsible grown up and now that I do eat my crusts -- even though it appears to have had no effect on my hair), so what do I do with my little boy who eats ONLY his crusts?