I'm looking for a fic. It might have been Steve/Tony, but I'm not sure. What I do remember is that Steve, having been in the army and used to rations, doesn't eat enough, despite the fact that he needs more calories since the serum. As a result, he's always hungry. I remember Tony thinking that Steve needed less calories then normal, finding out that wasn't the case, and helping Steve realize that it was okay to eat, that they wouldn't run out of food.
Thanks so much!!