it is metabolism, i am exactly the same!
if you're worried, see a doctor and have him check your healthy! things you can do to, is gain muscle rather than weight - this is what i'm currently doing and so far so good!
BUT when you're older, the likely hood is, if you have a diet filled with all things bad for you, this weight will catch you up!
hope i've help! feel free to send me an e-mail or something to let me know how your getting on :)
I think that can have something to do with your metabolism. I think if you go to your doctor and tell him/her that you think your metabolism is working faster then your calorie intake they should be able to help. And you can explain the question. Once your done typing your initial question, you can keep typing for the explanation. Just make sure to ask your question complete with question mark before explaining the situation. :)
Zoe is probably right. If you are trying to gain weight and it's tough, then you likely have a high metabolism. This will change as you get older, however, and eventually you will be able to gain weight.
There is a chance that you might have a certain disease however. If you ever feel light-headed or dizzy often, you should see your family doctor.
I dont like how it doesnt let you explain the question >:I.Well I've been underweight my whole life and its extremely hard to gain weight.I'll only sometimes gain a pound a year and usually I lose weight.I want to know if theres a disease when its hard to gain weight.
It could be a hyper active thyroid. People who have the condition are underweight and cannot gain weight. Ask your doctor about it for a proper diagnoses.
However, if you aren't unnaturally skinny, just count yourself lucky.