I wasn't quite 400lbs but close. I was over 380 at my biggest but I think I was closer to 400 then I thought. I was too big for my scale. I have got down to 359 for surgery. I'm 2 and a half months out and down to 305. All together 74lbs lost so far.
As a heavy weight is is a longer journey but it is completely doable. I wasn't sure I would be successful with the sleeve at first at my weight but I'm convinced I can now. There is a BMI over 50 board on OH and some of the people there started over 400 and have lost a LOT. It's very inspiring.