Contrary to what many people think, myself included, water may actually help with weight loss, at least in certain groups of people. Although water has no calories it appears that it may reduce appetite. Even though more randomized trials are needed, the available evidence confirms the importance of drinking water, especially when trying to lose weight.
This article will discuss the role water may play in losing weight.
Swap water for sweetened beverages
In a study of overweight women that normally consumed sweetened beverages, replacing these drinks with water resulted in a decreased daily caloric intake1. In a group of women following a weight loss diet, the women that reduced intake of sugar laden soda from 1-2 cans of soda per day to less than one can per day and increased intake of water from one-third to one-half of beverage intake saw a decrease in total energy intake that was maintained for the following year.
Water helps with weight loss in older adults
In a group of overweight older adults drinking water before a meal led to reduced energy intake1. The adults were assigned to two groups, both hypocaloric (low calorie), one group drank 500 mL of water before each meal while the other ate meals without drinking water first. After 3 months the group that consumed water before meals saw a 4 lb greater weight loss than the other group and a 44% greater rate of weight loss over the 12 week study.
In a group of overweight adult women (aged 25-50 years) on four different weight loss diets, increased water intake was associated with more weight and fat loss over 12 months3. An increase in drinking more than 1 liter of water a day led to a 5 lb weight loss over the year long study.
Water may not help with weight loss in younger adults
In a 2007 study, researchers found that drinking water before meals may lead to more weight loss in older but not younger subjects4. In a group of healthy, non-obese subjects ranging in age from 21 to 35 years old, consuming water before meals led to a decrease in hunger but did not affect energy intake, while in older adults (60-80 years) water intake before meals led to greater feelings of fullness and decreased energy intake.
How does water help with weight loss?
I have already shown that water intake may result in weight loss over time. But how exactly does water exert this effect? As mentioned, water may help decrease appetite and lead to less intake of food. Water may also replace sugar sweetened beverages, leading to weight loss from a lower intake of calories. Another important effect is that water has been shown to increase our metabolism, which I believe deserves its own article. I will cover this in a future blog.
- Although water contains no calories it may reduce appetite.
- In a group of overweight adults, water drank before meals reduced subsequent intake of food.
- In a group of overweight women, water intake was associated with weight loss over 12 months.
- Water intake likely leads to weight loss by: reducing intake of food when drank before a meal, replacing sugar sweetened beverages (thereby leading to lower caloric intake) and/or by its effect on raising our metabolism.
- Stookey, J. D., Constant, F., Gardner, C. D., & Popkin, B. M. (2007). Replacing sweetened caloric beverages with drinking water is associated with lower energy intake. Obesity, 15(12), 3013-3022.
- Dennis, E. A., Dengo, A. L., Comber, D. L., Flack, K. D., Savla, J., Davy, K. P., & Davy, B. M. (2010). Water consumption increases weight loss during a hypocaloric diet intervention in middle‐aged and older adults. Obesity, 18(2), 300-307.
- Stookey, J. D., Constant, F., Popkin, B. M., & Gardner, C. D. (2008). Drinking water is associated with weight loss in overweight dieting women independent of diet and activity. Obesity, 16(11), 2481-2488.
- Walleghen, E. L., Orr, J. S., Gentile, C. L., & Davy, B. M. (2007). Pre‐meal water consumption reduces meal energy intake in older but not younger subjects. Obesity, 15(1), 93-99.