Go to Lucky Boy restaurant in Pasadena (California, where all the roses are) and ask for 2 bacon breakfast burritos. I think there's something like 3200 calories in each one.
If you workout then eat theese things: Chicken breast, egg and drink protein shake, that should give you some extra weight. Just don't eat shittons of fastfood, that aint good,
You could always try energy bars and protein drinks, Ensure and meal substitutes like Boost are often used to get malnourished people up to par. If you really are skinny because of lack of nutrients go for it but if it is because of genes and you just feel embarrassed I suggest support groups. You are who you are, cannot be anyone else. I dont know how old you are but I always thought I was on the small size, worst of all my body does not develop "cut" lean muscles. I was in the Marines, in the best shape of my life and could do or almost do as good as anyone else. And I looked like a kid. Benching 280 and running the three miles in 15 minutes. Weighed 145. Look at Manny Paquiao he looks small and not very cut but he is one of the best fighters in the world. 5000 calories is way more than even the biggest body builders need. In all honesty if you are really worried you should be asking a doctor not internet strangers.
Thanks guys every thing you guys put down in this thread I'm actually taking notes(in my brain). Lol keep 'em comin'! All this food talk is making me hungry, I'm also going to my memorial parade soon, I'll try to take some pics for you guys to see my "wing". I just have a very high metabolism. So everything I consume is turned into energy right away. When I meant by high, I mean really high, even if I eat a buffet of food about 1-3 hours later I'll be hungry again.
Welcome to the club. I ate 2 of the aforementioned breakfast burritos in one sitting, had a In-N-Out 4x4 for lunch, then went to Lawry's and had a ton of steak. I woke up the next morning hungrier than ever