Underweight and fast metabolism issues .. help ?!?!?!

Underweight and fast metabolism issues .. help ?!?!?

So I am 18 years old, 5''2 and like 90lbs. At my age, I should be 106lbs-121lbs. So basically I am 16lbs underweight, but I eat ALOT. Both healthy and junk food. I even started some excercise because people tell me it tones my muscles and allows me to get bigger. But even still, it wont work. Is there anything I can take that wont have any dramatic side effects, etc. ? And I'm no druggy so addiction is not a problem. I hate medicine, but am willing to take it in this case. Any suggestions on food, medicine, etc. ?

I'm exactly like you!
Frustrating isn't it? Especially when people assume you're starving yourself of something!

Anyway what i've started to do is add an extra 500 calories to my daily consumption.
So say you eat 2000 calories a day, add 500 to that.
Stay away from junk food - this won't help you gain weight because it has all the bad fat in it that just goes straight to the arteries.

Instead try these high in calories and good fat foods:

Wholemeal bread, peanut butter, nuts, icecream, eggs, meat, fish, mayonaise, vegetables, protien bars, milk, etc etc.
Just look for anything with a high calorie content in it and go for it.

If you want to gain 1lb...you'll have to consume 3500 calories.

Don't give up on trying to gain muscle...because muscle weighs more than fat, so keep trying (=

Good luck ^o^