To keep things short, read this:

http://forum.zeroinginonhealth.com/showthread.php?tid=152



Hilary McClure wrote:
> Have any of you come down from major obesity to normal weight or even 
> leanness? I've been reading in a popular political blog--a sub-group 
> there of people struggling with their weight and health and posting on 
> those topics regularly. It's amazing to me how none of them know the 
> first thing about metabolism, carbs, insulin. I thought there was 
> growing awareness of those things among educated people, but I guess I 
> was wrong. Not even any mention of Atkins, let alone Cordain, Eades, 
> Taubes, or Rosedale. They probably think that's all a bunch of 
> dangerous hype, and they either think their genes are cursed, or they 
> are wracked with guilt over their laziness and lack of willpower. They 
> have no idea that it's just ignorance and that it's actually not that 
> hard or painful to lose weight. I could find amusement in it, except 
> that these people are in a lot of pain.
>
> Here's one real question I have:
> If you were trying to come down from a BMI of 50-something (like if I 
> weighed 400lbs at 5'-11"), would you exercise at all, or just go 
> zero-carb? (Well, even meat has carbs, but I mean really low.) These 
> people think they have to not only starve themselves, but exercise as 
> well. I think they are cutting calories but not carbs, so they're 
> shooting themselves in the foot. They're not maximising fat-burning, 
> and are losing precious lean mass as well as fat, if they're losing at 
> all. It seems to me that getting their 400 pounds off the sofa and 
> over to the refrigerator is workout enough. Getting up off the toilet 
> is a major leg-press. Just to be able to move at all at 400 lbs. means 
> they've actually got some muscles under there. Seems like they should 
> go on full Atkins for maybe a year before actually trying to do any 
> formal exercise, and not wreck their joints any further, or whatever 
> other damage they might do. See, with all that fat, not only are they 
> putting tremendous extra loads on all their joints, but the fat also 
> puts their whole body in an inflammatory state, including their 
> joints, I would expect, compounding the damage.
>
> Thanks,
> Hilary