I'm not trying to be a smartass, but if you want to bulk up, you need to either hit the gym HARD for months on months, or do it wrestler style and bust out some steroids. In all seriousness, though, like Tatty said, Don't wing it. If you're as overweight as you implied (didn't you say 400 lbs somewhere?) you need to start slow and get you body used to the fact that your going to be using in new ways for quite some time to come. The rule for fat folk is to start by doing 10% of what you want to do. Start with ten minute walks, proper diet, and light weights for the first couple of months. It takes a awhile for a metabolism that's been trained to behave a certain way for years to realize that shit's going to change. Like Gia said, cutting out sugary drinks really goes a long, long way towards a headstart. Make sure you're feeding yourself at regular intervals, so your body doesn't think your starving and stores any fat it gets. Work your way towards a rigid routine. There's no rush. You'll end up injuring yourself if you push it too hard too early on. I made the mistake of hitting the weights entirely waaaay to hard when I decided I was going to start working out. I felt great the next day, but the day after that, DOMS (delayed onset muscle soreness) set in and I couldn't even extend my arms or walk without being in excruciating pain. It went away after about 24 hours. Now I'm just going slow, working my way towards a healthier body. Rome wasn't built in a day, frankie. Take it slow, and good luck.