I found that when I weighed more, I had more flexibility with regard to the quantity of carbs and the number of calories I ate. However, I never went as high as 100 grams of carbs a day -- more like 50 or 60. After losing 90 pounds, I think that I have to more closely count carbs in order to lose.

You might want to check out the Triple Digits Club under Lowcarb Support Focus Groups. It's for people with 100 or more pounds to lose. People there might have some insight into your question.