I have been on Wellbutrin 200 mg BID for a little over a year. It seemed to increase my metabolism. My appetite was the same. I've always eaten the same foods (day after day; LOL, I have a food phobia about texture/taste/smell and eat only certain foods, but that's a whole other issue). I dropped nearly twenty pounds over the first two months without changing the amount or type of food. My activity increased a little, but not so much that it would account for the weight loss. Due to the weight loss, my doctor tested me for everything and then some (hyperthyroidism, diabetes, etc). All were negative. My weight has maintained the same after those two months.
As far as Wellbutrin helping- my anxiety is less, and my panic attacks have definitely decreased. I should also point out that I started taking Seroquel at the same time I started Wellbutrin, so it may be that it's the combination that's working pretty well for me.