The Efficacy of Increased Water Consumption as a Weight Loss Strategy

The population of older adults continues to grow in the US, as does the prevalence of overweight and obesity within this group. Several factors may contribute to age-related weight gain, such as a reduced energy expenditure and energy intake requirements, and a susceptibility to energy over-consumption. Serious consequences result from overweight and obesity, such as increased risk of chronic disease, decreased quality of life and increased healthcare costs. Thus, effective weight management strategies are needed which target this population. Reducing energy-containing beverage intake and increasing water intake are often suggested as strategies for weight loss, yet surprisingly little data exists to support the effectiveness of these strategies. Previous studies have shown that older adults consume fewer calories at a laboratory test meal following a water preload, but it is unknown whether this reduced energy intake can be sustained over time to produce weight loss. Epidemiological studies using self-reported dietary intake have shown that substituting water for energy-containing beverages decreases total energy intake, and that drinking > 1L of water is associated with greater weight loss in overweight women compared to overweight women who consumed < 1L daily. However, these studies were a secondary analysis of a trial comparing multiple weight loss strategies and increasing water consumption was not a primary outcome of interest. To directly address this issue, we hypothesized that increased water consumption would increase weight loss in healthy overweight and obese older adults in combination with a 12-week hypocaloric diet as compared to a hypocaloric diet alone. As hypothesized, older adults randomized to the increased water intake group demonstrated greater weight loss than those randomized to the diet alone group (7.4 kg vs. 5.5 kg, respectively). Because energy-containing beverages contribute to total energy intake without a concomitant reduction in food intake, substituting water or energy-free beverages for energy-containing beverages appears to be an effective weight management strategy for older adults.