eat more calories then you burn.....

my metabolism is pretty fast because I workout everyday, and i eat every few hours, plus i'm only 23....When I am putting on weight I usually take 3 weight gainer shakes a day in a cup of milk which accounts to about 1200 calories alone.

I use Real Gains...u can google it, its affordable and quick and easy to fix. I wouldn't rely on shakes but add them to your diet you already have going on. Real Gains provides you with carbs and protein, its not just a protein supplement so thats why i would recommend that over ON 100% whey, which is primarily for the BCAA's and protein. It doesn't have the carbs and cals that Real Gains will give you.

I wouldn't suggest eating a bunch of chocolate or burgers to gain weight. Lots of protein and complex carbs.....oats, greens, i like grits, ww bread for your carbs, eggs and lean meats for your protein source.