1. ¹Department of Human Nutrition, Foods and Exercise, Virginia Tech, Blacksburg, Virginia, USA
2. ²Department of Health Sciences, Ferrum College, Ferrum, Virginia, USA
3. ³Department of Human Development and Center for Gerontology, Virginia Tech, Blacksburg, Virginia, USA

Correspondence: Brenda M. Davy (bdavy@vt.edu)

Received 22 December 2008; Accepted 14 June 2009; Published online 6 August 2009.

Abstract

Water consumption acutely reduces meal energy intake (EI) among middle-aged and older adults. Our objectives were to determine if premeal water consumption facilitates weight loss among overweight/obese middle-aged and older adults, and to determine if the ability of premeal water consumption to reduce meal EI is sustained after a 12-week period of increased water consumption. Adults (n = 48; 55–75 years, BMI 25–40 kg/m²) were assigned to one of two groups: (i) hypocaloric diet + 500 ml water prior to each daily meal (water group), or (ii) hypocaloric diet alone (nonwater group). At baseline and week 12, each participant underwent two ad libitum test meals: (i) no preload (NP), and (ii) 500 ml water preload (WP). Meal EI was assessed at each test meal and body weight was assessed weekly for 12 weeks. Weight loss was ~2 kg greater in the water group than in the nonwater group, and the water group ( = -0.87, P < 0.001) showed a 44% greater decline in weight over the 12 weeks than the nonwater group ( = -0.60, P < 0.001). Test meal EI was lower in the WP than NP condition at baseline, but not at week 12 (baseline: WP 498 25 kcal, NP 541 27 kcal, P = 0.009; 12-week: WP 480 25 kcal, NP 506 25 kcal, P = 0.069). Thus, when combined with a hypocaloric diet, consuming 500 ml water prior to each main meal leads to greater weight loss than a hypocaloric diet alone in middle-aged and older adults. This may be due in part to an acute reduction in meal EI following water ingestion.