Olanzapine causes the most weight gain out of all the anti-psychotics, and is bad for serum glucose, triglycerides and cholesterol.

Exercising and watching what you eat is the best thing if you are going to stay on it. Even doing everything right, you might not be able to lose much weight.

When I got so bad I needed an antipsychotic I demanded one that is weight neutral and told my pdoc that I would refuse any of the others like olanzapine.