Weight Gain?!

Weight Gain?

I am trying to gain some weight. I am 21 yrsold 5 10 135 and I feel small. I dont get it my dads 53 yrsold 6-3 and weighs 210 and has a body of a body builder. I eat like crazy and dont gain a lb. First question is why cant I gain weight. Should I work out while trying to gain weight or just sitt around. Also I bought MASS XXX from gnc. I tried weight gainer did nothing but cause gas lol.
Please help.

I'm going to guess that you are pretty active and probably have a high metabolism. I'd also bet that you have almost no body fat and if you didn't keep eating you'd probably lose some weight.
The bottom line is that you need give your body the help it needs to store up some fat. Don't work out until you have gained at least 8 to 10 pounds.Your diet will be the biggest factor. Stick to the dairy products; shakes made with whole milk, ice cream, and bananas. Btw, bananas have a natural steroid in them that will also help you gain, but you have to eat alot (preferably 6-8 a day).
Eat cheese, red meats, lots of green vegetables and more bananas.
Drink lots of water. At least 120 oz. per day.
Every morning, eat a large breakfast with at least 3 eggs, bacon, biscuits and gravy, 2 glasses of whole milk.

The faster you eat, the more you'll be able to eat. Everything else in your world needs to slow down. Sleep more. Rest more and eat bananas while you do it. Showers should start out warm and gradually make the water as cool as you can stand it. Think of it as a job you want to really succeed in, and you'll gain the weight.