I'm not going to say you haven't lost eight pounds in three days, but I will say that most of that was water weight and the rest was probably muscle. A pound o

I'm not going to say you haven't lost eight pounds in three days, but I will say that most of that was water weight and the rest was probably muscle. A pound of fat is roughly 3500 calories. In order to lose eight pounds of fat in three days, you would have had to induce a caloric deficit of over 9000 calories per day. A note to everyone: The most weight you can healthily lose is about two pounds per week. More than that and you're going to start losing a measurable amount of muscle mass. The exception is when you first start out exercising and eating properly, but that should only last for a couple of weeks.