You may have recently learned from several online sources that you have been ruining your metabolism and weight control efforts, simply because you have been drinking water that is room temperature. Their answer: Switch to cold water, and "ignite your body's fat burning furnace". Our question: Is there any truth to this?
Where Did This Idea Come From?
Prevention.com posted an article "10 Diet Mistakes That Slow Metabolism", which has been reposted on everything from yahoo.com to ABC news. Of particular interest, #4 on the list is that your water is room temperature. They state,
"German researchers found that drinking 6 cups of cold water a day (that's 48 ounces) can raise resting metabolism by about 50 calories daily — enough to shed 5 pounds in a year. The increase may come from the work it takes to heat the water to body temperature."
What Does The Research Say?
First of all, we are referring to what is called "water-induced thermogenesis". Thermogenesis refers to heat production within the body. As you may know, we measure the heat produced by the body kilojoules or kilocalories (Calories) during rest — also known as Resting Energy Expenditure (REE).
The uncited "German" article is mostly likely referring to either a study done in 2003, and/or a follow-up study done in 2007.
In the 2003 study, participants drank 500 ml of water (16 oz) at 22º Celsius (71º F). An hour later, their REE had increased to and spiked 30% higher than where they started.
Wow, 30% !?
Well, it was only about a 0.32/minute Calorie difference. Not much.
In the 2007 study, similar results were found, but with a 24% increase after 90 minutes of drinking 16 oz of water. The authors estimated that it took approximately 7 Calories to heat the cool water up over the 90 minutes, and that the volume of water matters — 50 ml of water had no effect on REE.
In 2006, researchers revisited this idea of water-induced thermogenesis and found that,
"Cooling the water before drinking only stimulate a small thermogeneic response, well below the theroetical energy cost of warming the water to body temperature. These results cast doubt on water as a thermogenic agent for the management of obesity."
Actually, in comparison to several of the previous studies, this is what we find:
|Boschmann et al., 2007||500 ml||24% increase after 90 min|
|Brown et al., 2006||518 ml||4.5% increase over 60 min|
|Boschmann et al., 2003||500 ml||30% increase after 60 min|
|Brundin & Wahren, 1993||375 ml||2% increase over 2 hours|
|De Jonge et al., 1991||Not Stated||No|
|Dulloo & Miller, 1986||200 ml||No|
|Felig et al., 1986||400 ml||No|
|Gougeon et al., 2005||750 ml||No|
|Komatsu et al., 2003||300 ml||2.7% increase over 2 hours|
|LeBlanc et al., 1984||600 ml||No|
|Li et al., 1999||280 ml||No|
|Paolisso et al., 1997||Not Stated||No|
|Sharief & Macdonalde, 1982||292 ml||No|
|Modified from Brown et al., 2006|
As you can see, there are mixed findings on water-induced thermogenesis, but the majority of the research supports little to no substantial increases in energy expenditure at rest (metabolism) from drinking cold water. So, keep drinking your water, cold or warm, but do not expect to "ignite your body's fat burning furnace". Any effects on weight control, are likely a result of water consumption reducing energy intake from other foods.