Is it possible to have a huge metabolism as in 3500 a day?

I literally never feel full. I could count on one hand how many times I have felt satisfied over last few years. I am not really fat just a little podgy around the middle( 5foot5 and 9.3) but I am steadily gaining a few pounds per year. I just can't stop eating. I eat at least 200/300g of choc a day,crisps and biscuits along with one or sometimes two huge healthy dinner. I do no exercise so although I dont look fat my body is so flabby and i have no muscles at all. I think I consume approx 3500 a day if not more. I feel so unhealthy. No matter what I eat I am never, ever ever satisfied. SO SO annoying and costing me a small fortune. despite having a hot pot with meat and veg 1 hour ago I want another dinner now.Tried going to gym but got more hungry and ended up putting on weight