Unfortunately I loaned my Atkins books to someone so I can't look it up, but it was my understanding that each person needs to find their own critical carb level. I thought that some people have a very high level and can eat quite a lot of carbs without regaining weight and others will never be able to go above 30.

My DH lost 75 pounds doing low carb and improved his cholesterol to the point where he no longer needs meds. He is definitely a carb addict -- loved potatoes and sweets. He is 5'10" and now 145 pounds. He lost weight very rapidly on 50 - 60 carbs per day -- it seemed like he just 'melted'! Now on Maintenance he is up to about 100 carbs per day just to maintain his current weight. If he drops below that, he will start to lose, and he should not lose any more weight. He has added back whole grain breads (Natural Ovens 'Hunger Filler' with 7 carbs), sometimes whole wheat pasta, quite a bit of fruit daily, and occasionally he has a baked potato or brown or wild rice. As long as he sticks with the whole foods and avoids the processed, refined carbs he has no problem maintaining his weight. However, there is not doubt in my mind that if he would start eating sugar and white flour again his weight would balloon.

I, on the other hand, need to stick with 20 carbs per day to lose, and I doubt that I will ever be able to eat even the whole grains or fruits except as a rare, maybe once or twice a year, treat.

So, I guess that my answer would be that the maintenance carb level is very individual and there may be others like my DH who can maintain on 100 carbs per day and some like me who need to keep the level much lower.