"When two groups of subjects both eat the same number of calories (but provided by diets of different macronutrient compositions) and maintain the same activity level, yet one group loses more weight than the other, the group losing the greater weight is said to have a metabolic advantage." - Dr. Michael Eades, M.D.
P.S. The evidence continues to show lower carbohydrate diets result in greater weight loss and less hunger, than calorie reduced diets.
More specifically, this type of diet for weight loss is said to provide a metabolic advantage.