In sensible circumstances Low Carb diets work of course under the supervision of a qualified professional )
This is a recent study:
Meckling KA, Sherfey R A randomized trial of a hypocaloric high-protein diet, with and without exercise, on weight loss, fitness, and markers of the Metabolic Syndrome in overweight and obese women. Appl Physiol Nutr Metab. 2007 Aug;32(4):743-752.
The subjects were divided into two main groups – high carb (3:1 carb:protein) and low carb (1:1 carb: protein) and then subdivided into exercise (three times per week) and non exercise groups within each diet group.
Weight loss after 12 weeks was as follows: 4.6lbs for high carb no exercise group 8.8lbs for high carb with exercise group 10.1lbs for the high protein-low carb -no exercise group and 15.5 lbs for the high protein, low carb with exercise group.
“What’s really interesting is that the high protein, low carb group was superior for weight loss over high carb with exercise. And it was 75% superior when combined with exercise.”
(Alwyn Cosgrove)