With all the mocha lattes, soda, sweetened juices and other flavored beverages we guzzle down each day, there’s a good chance you’re not drinking enough water. Every system in our bodies depends on water, which flushes toxins from vital organs and carries nutrients to cells.
What’s more, just imagine all of the calories (and money) you could save if you passed on those flavored coffees or other sugary drinks and tried some good, old-fashioned H2O. And it’s not just the calories saved; studies are showing that drinking water may actually increase the number of calories you burn, not only during exercise, but even when you’re sitting around doing absolutely nothing!
According to a study in the International Journal of Obesity, an Israeli research team found that drinking cold water significantly elevated the resting energy expenditure (REE) in overweight children. Along with previous research showing water-induced REE elevation in adults, this suggests that drinking water could help with weight loss or maintenance.
For this study, 21 overweight and obese but otherwise healthy children (11 boys, 10 girls) aged 7–12 years were selected. For children, overweight is defined as having a body mass index in the 85th percentile or greater for their age and sex, while obesity is defined as a BMI at or above the 95th percentile. (For adults, a BMI of 25-29.9 is considered overweight, and a measure above 30 is considered obese.) The children in the study had a BMI ranging from 20.4–33.5.
The children came to the research facility in the morning, after at least 12 hours of physical inactivity and complete overnight fasting, during which time they were not allowed to drink any water. The participants were put in bed and were covered with a ventilated hood connected to a portable metabolic cart for breath-by-breath respiratory gas exchange measurements. The baseline measurements lasted for 20 minutes and the mean REE of the final 10 minutes was defined as the baseline REE. During the study period, each child was shown a non-action movie of their choice to keep them from growing bored and to discourage big movements.
After the baseline REE was determined, the children were given 10 ml kg-1 based on their body weight of natural mineral water with a temperature of 4 degrees Celsius. The authors noted that mineral water was used over tap water to control for solute concentrations. It took the children two to three minutes to drink the water, after which they resumed their lying position under the ventilated hood and continued to watch the movie. Their REE was measured for another 66 minutes at three-minute intervals.
The researchers noticed a significant drop in REE immediately after the children drank the water, followed by a rise in energy expenditure. The REE was significantly higher than baseline values at 24 minutes after water ingestion and at most times thereafter. At 57 minutes after drinking the water, researches noted the highest REE, which was a 25% elevation from baseline.
This weight loss was attributed to the effect of water-induced thermogenesis (production of heat) in which the children’s energy expenditure was increased with no additional energy intake. Therefore, it had a “negative caloric effect.”
Researchers concluded: “Consuming the recommended daily amount of water for children [1,800 ml] could result in an energy expenditure equivalent to an additional weight loss of about 1.2 kg per year just by adhering to general water drinking recommendations for children.”
As for the effect of water on adults, they wrote: “In a study on older adults, drinking 500 ml of water before each meal increased weight loss by +2 kg over a 12-week period, explained only in part by a reduction in the energy intake of the meal; water-induced thermogenesis could have also assisted in the observed weight loss with pre-meal drinking.”
Now 2 kg, which is roughly 4.4 lbs, may not seem like a game-changer when it comes to your waistline. But if there’s an easier way to lose weight naturally, I haven’t heard it!
And remember, that’s how much your body could burn simply by increasing your water intake. If you were to replace the high-calorie juices, soda and/or sports drinks you consume with water, you could also be saving yourself a tremendous number of calories each day, which should speed along your weight loss goals.
And for the sake of the environment and your wallet, avoid drinking from disposable plastic water bottles whenever possible. Instead, get yourself a sturdy reusable one and fill up before you leave the house.
 Dubnov-Raz1, G, et al. Influence of water drinking on resting energy expenditure in overweight children. International Journal of Obesity (2011) 1–6.