you'll find that when u r happier ur weight doesn't matter but regular diet and exercise usually do the trick
We all react to medication differently, but I've seldom, if ever, heard that benzodiazapines cause weight gain. Antidepressants are another story. But, if your experience was that you gained weight while on a benzo, you will need to explore your options with your doctor.
I don't think you should be looking for a psychotropic medication to help you lose weight. That could be an unhealthy and possibly dangerous expectation.
Far better to deal with your anxiety and weight loss as seperate goals that may actually work together. You wouldn't ask Jenny Craig to prescribe a benzo and these classes of drugs are not therapeutic for weight loss.
Peace
Greenlydia