So I've been on neuroleptics for about a decade. I gained around 50 pounds and have never been successful in losing it. So far on my latest attempt I've lost 25 pounds  and am on my way to lose more.
The strategy: 
1. Intermittent fasting- 16/8
2. Metformin - off label weight loss drug by prescription
3. Caloric restriction
4. Low carb for first meal - I meal prep salmon vegtable quiche and navartan korma curry with cauliflower rice
5. Exercise