Previous research showed that weight loss in response to weight management program is influenced by total energy intake and water consumption. Whether or not purified water affects weight management is currently unknown. Methods: An intervention study of 29 middle-aged obese women who reported < 1L/day drinking water at baseline was carried out in Yaounde, Cameroon. Participants were randomly assigned to one of the two groups: (i) hypocaloric diet + physical activity + reverse osmosis infrared filtered water (ROIFW), and (ii) hypocaloric diet + physical activity. Weight, waist circumference and body fat were assessed at baseline, 4, 8, 12, 16, 20, 24, and 28 weeks. General Linear Model procedure of repeated measurements was used to determine whether weight loss as well as changes in waist circumference and body fat differ between the two study groups.