What amount will i lose on ketosis in the first 2 months?

Variable but likely: It depends on how much you weigh now. For example, a patient of mine who was 425lbs lost 80lbs in his first 9 weeks. Much more common is a patient losing 20 lbs in first two months as they don't have near as much to lose. However, if you need to lose 30 total-50 total, for example, most people who go into ketosis will lose around 20 in 2 months based on my estimation of patients I'v seen.