"People who drank diet soda did not appear to consume more sugary and fatty foods than did those who chose water, according to a study in the American Journal of Clinical Nutrition. Researchers also found that diet-soda drinkers ate fewer desserts at six months compared with their habits before the study started, while those who drank water consumed more fruits and vegetables than they had previously."http://www.reuters.com/article/2013/02/20/health-dietdrinks-idUSL4N0BK0GG20130220
Is this a question of calorie reduction vs nutrient starvation?