I know all about cravings. When I quit smoking, I craved cigarettes. When I cut out carbs and sugar, I suffer for about 3 days of the most intense sugar-cravings imaginable. When I’m thirsty (oddly enough), I crave carbs (somebody explain that to me?) But…I crave protein all the time. I have never heard anybody else describe cravings for protein such as I have always experienced. Is this just a metabolic variation, or something? I’m sure I eat more than the RDA.
I started working out a lot last year (my first year in college). I used to (and still) get these too. I would eat chicken all the time (unlimited mealplans are the best). And protein bars. I think your body just knows what it needs.
As far as protein and exercise:
http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=143385
I have also heard that men need more protein than women, but I’m not sure from where.