Water consumption increases weight loss during a hypocaloric diet intervention in middle-aged and older adults

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/m(2)) 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 (beta = -0.87, P < 0.001) showed a 44% greater decline in weight over the 12 weeks than the nonwater group (beta = -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.

Figure 1

Study design.

Figure 2

Weight loss among water and nonwater group participants over the 12-week intervention.

Figure 3

Visual analog scale (VAS) ratings of (a) hunger, (b) fullness, and (c) thirst among water and nonwater group participants at baseline in the water preload and no-preload ad libitum meal conditions. Following completion of the 0 min VAS scale, the water preload was provided (water preload condition) (a); subjects completed the next VAS scale at 30 min, and were immediately provided with the ad libitum meal (b). VAS scales were completed following the ad libitum meal at 60 min (c), and at subsequent 30-min intervals until the completion of the 150-min testing period. *Significant difference between preload conditions, P < 0.05. No group differences were detected.

Figure 4

Visual analog scale (VAS) ratings of (a) hunger, (b) fullness, and (c) thirst among water and nonwater group participants following the 12-week intervention in the water preload and no-preload ad libitum meal conditions. Following completion of the 0 min VAS scale, the water preload was provided (water preload condition) (a); subjects completed the next VAS scale at 30 min, and were immediately provided with the ad libitum meal (b). VAS scales were completed following the ad libitum meal at 60 min (c), and at subsequent 30-min intervals until the completion of the 150-min testing period. *Significant difference between preload conditions, P < 0.05. No group differences were detected.