Using food as a cooking fuel to cook other food? I was thinking about it and we use charcoal, gas, wood chips, etc to heat our food; for obvious reasons and since they burn for a long time.

But what if, for example, you set a few steaks on fire and use those steaks to cook a hamburger? Would it improve the taste of the hamburger?
If you just want the concept, there are pasta sauces involving egg or egg yolk where the heat from the pasta is the only thing that cooks the egg. In that way you cooked your food with food, but you didn't have to do without either piece of it.