PSA: Do not fast an overweight reptile to help them lose weight
1) It probably won’t work very well, because drastically cutting off food will likely cause them to just slow their metabolism to compensate.
2) Fasting an overweight animal can actually make them more likely to develop fatty liver disease. When it goes without food for a long time the body starts sending fat to the liver to be converted into energy. The liver can’t handle all the influx of fat and so stores it in liver cells, eventually leading to fatty liver disease.
What should you do instead? Feed them as often as you usually would (assuming you were feeding them on a species-appropriate schedule) to keep their metabolism up, but make the meals smaller.