Water is essential to life and most people don’t drink enough of it. In fact, most people fall well short of the recommended eight glasses of water daily. No doubt we need to drink enough water for optimal health but does drinking more water offer benefits if you’re trying to lose weight? You’ve probably heard people say it does but does science support this idea?
Drinking More Water to Lose Weight: Is There Science to Support Its Benefits?
Drinking more water could theoretically help with weight loss in several ways. Consuming more water might help with appetite control so you eat less. Drinking more water could also give your metabolism a subtle boost and lead to increased energy expenditure. Is either of these ideas supported by science?
Some research supports the idea that water helps with weight loss. A study carried out in 2008 suggests water may be underappreciated as a weight loss aid. In this study, healthy, middle-aged and older adults, all trying to lose weight, were divided into two groups. Both groups ate a similar diet. The only difference was one group drank 2 glasses of water prior to meals while the other group didn’t. After 3 months, the group who drank water lost more weight (15.5 pounds) relative to the other group who lost an average of only 11 pounds.
How might water work its weight loss magic? One way is by suppressing appetite. One study showed drinking more water prior to meals reduces calorie consumption by a modest amount, about 75 to 90 calories per meal. That doesn’t sound like a lot but it adds up over time. It’s not surprising that water has some moderating effect on appetite, but does it boost energy expenditure as well?
The Effects of Drinking Cold Water on Metabolism
Chalk up another point for drinking more water. Evidence suggests that drinking water modestly increases the resting metabolic rate. A study in overweight children showed drinking cold water raised their resting metabolic rate by about 25% and the effect lasted for about 40 minutes. The fact that the water was cold could be key. Your body has to expend a little more energy to raise cold water to body temperature.
What about adults? A small study in adults showed drinking more water transiently boosted resting energy expenditure. In this study, drinking approximately 2 cups of water increased energy expenditure by 30%. Another study showed more modest benefits. In this study, drinking 2 cups of cold water only sped up resting metabolic rate of participants by about 4%. A more encouraging study in overweight women showed drinking more water was linked with greater weight loss independent of other factors like diet and physical activity.
Other Benefits of Drinking More Water
Did you know water makes up about 60% of the composition of your body? Despite its importance, it’s easy to forget about the importance of drinking it, but not doing so can lead to mild dehydration. When you’re even slightly dehydrated, you may feel fatigued or even experience a headache. Some people who complain of feeling tired all the time are actually suffering from the effects of mild dehydration due to not drinking enough fluid. The risk of mild dehydration is even higher if you work out and sweat a lot.
Your kidneys also need a healthy supply of water. People who don’t drink enough of “the universal liquid” are at higher risk for kidney stones. Not drinking enough water, especially when it’s hot outside, places women at greater risk for urinary tract infections as well. Plus, you need enough water, along with fiber, to keep your bowels working properly. When you don’t drink adequate water, you may have the unpleasant experience of being constipated. As an interesting aside, a study showed drinking carbonated water helps with constipation, even more than plain water.
How Much Water Should You Drink Each Day?
According to the Institute of Medicine, the average women should drink around 9 glasses of water a day, a total of about 2.2 liters. That’s a bit more than the 8 glasses a day that most sources recommend. Men need closer to 3 liters. Remember, exercise and hot weather increases fluid requirements even more.
How do you know if you’re meeting your body’s demand for water? If you are, your urine should be pale yellow, amber or straw in color. If it’s very dark yellow or a shade of brown, you’re not drinking enough. The color of your urine is a pretty good indicator of how hydrated you are and whether you’re consuming enough water, although health problems that cause bile or blood to enter your urine can cause it to appear darker or even red in color. Some foods, medications, and supplements may also cause your urine to change colors. Examples of foods that can do this include asparagus, beetroot, some berries, fava beans, carrots, and rhubarb.
The Bottom Line
Drinking more water could make it easier to control your weight, although the benefits are modest. Where you’ll get the most benefits is when you replace sugary drinks and soft drinks, including fruit juice, with water. When you consider a serving of soda has 140 calories and almost 40 grams of sugar, it’s easy to see how making this switch could yield big dividends from a weight loss perspective. If you need something “bubbly,” substitute seltzer water for soft drinks. Otherwise, make water more fun to drink by adding a squirt of citrus fruit, fresh herbs or slices of cucumber.
Make drinking more water a daily habit. Carry water with you to the office in a stainless steel container and sip on it throughout the day. Lay your water container out in the morning so you won’t forget it. Happy sipping!
WebMD. “Water May Be Secret Weapon in Weight Loss”
Int J Obes (Lond). 2011 Oct;35(10):1295-300. doi: 10.1038/ijo.2011.130. Epub 2011 Jul 12.
Science Daily. “Drink water to curb weight gain? Clinical trial confirms the effectiveness of simple appetite control method” August 2010.
J Clin Endocrinol Metab. 2003 Dec;88(12):6015-9.
WebMD. “Drinking Water May Speed Weight Loss”
J Clin Endocrinol Metab. 2006 Sep;91(9):3598-602. Epub 2006 Jul 5.
Obesity (Silver Spring). 2008 Nov;16(11):2481-8. doi: 10.1038/oby.2008.409. Epub 2008 Sep 11.
WebMD. “6 Reasons to Drink Water”
GI Society. “Carbonated Water May Help Dyspepsia & Constipation” January/February 2013.
Mayo Clinic. “Water: How much should you drink every day?”
WebMD. “Changes in Urine Color”
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