My whole life I have had a very fast metabolism. Others in my family are similar. I have difficulty gaining weight but I am not overly thin. I eat 5000-7000 calories a day. I have seen two different doctors. My metabolism is sometimes a problem for me. When I stay with friends or relatives I sometimes feel like a pig eating all their food but I am just too hungry. It can be embarrassing and I am afraid people will think I am weird.