While I have no information regarding the percentage of over weight people who are using carbohydrate restriction to control their weight, here is a recently published comparison study that confirms the superior effectiveness of low-carb eating for weight loss: The A TO Z Weight Loss Study: A Randomized Trial JAMA. 2007;297:969-977.

Here's comment by Dr. John Briffa, a London Physician:

"Today sees the publication of a study in the Journal of the American Medical Association in which the effectiveness of four diets was assessed over a year-long period [1]. Researchers at Stanford University School of Medicine ascribed women to eat either the Atkins’ diet (low carb), Zone diet (carb, protein and fat in the ratio of 40:30:30), LEARN diet (based on standard food pyramid) and the Ornish diet (low fat, high carb).

At the end of the year it was revealed that the most effective regime was the Atkins diet, with an average weight loss of 10.4 lbs. Average weight loss on the Zone, LEARN and Ornish diets were 3.5, 5.7, 4.8 lbs respectively. Note here that the effectiveness of the Atkins diet was approximately double that of higher carb diets (Ornish and LEARN).

But that’s not all, because the Atkins’ diet ... brought about significant improvements in one or more health measurements such as blood triglyceride levels, ‘healthy’ high density lipoprotein (HDL) cholesterol levels and blood pressure. Taken as a whole, the Atkins’ diet beat the other ones hands down.

This result may come as a surprise to those who continue to tout the ‘benefits’ of a low fat diet. However, we can be pretty sure these findings are precisely what individuals who use low and lower-carb diets in practice would expect. I, personally, have found lower-carb diets broadly beneficial not just in terms of weight loss, but in normalizing physiology and biochemistry too."

To learn how Taubes' book has affected people struggling with weight loss issues, I suggest you Google "Gary Taubes Low-carb forums."