I think it truly just depends on a person's genetic makeup. I also see a correlation between a higher starting weight (in my opinion, those with higher weights seem to lose large amounts quickly - then slow down as they get closer to goal.) I for one usually start out with pretty decent losses, then slow down drastically. And I'm sure diet also plays a roll. Many people who are on a Keto plan do tend to lose quickly as well. I'm a lot like you though - I'm happy with any loss - as long as the number is going down.