Previous reports have suggested that drinking water significantly elevates the resting energy expenditure (REE) in adults. This study examined the effect of drinking water on the REE of overweight children to assess possible effects on weight control. 21 overweight but otherwise-healthy children (age 9.9±1.4 years, 11 males) drank 10 ml/kg of cold (4°C) water. REE was measured before and for 66 minutes after water ingestion, for 66 min. Immediately after drinking water, there was a transient decrease in REE, from a baseline value of 3.32±1.15 kJ/min to 2.56±0.66 kJ/min after 3 minutes. A subsequent rise in REE was then observed: this was significantly higher than baseline at 24 min (3.89±0.78 kJ/min (P =0.021)), and at most time points thereafter. Maximal mean REE values occurred at 57 min after water drinking (4.16±1.43 kJ per min (P=0.004)), and were 25% higher than baseline. The authors estimated that consuming the recommended daily amount of water for children could result in an energy expenditure equivalent to an additional weight loss of about 1.2 kg per year.

 

These results are interesting, but some caution is needed. No control data are available, so an increase of REE may occur over the 60 min measurement period even without water intake. Measurement of REE in children is not so easy as in adults. Fidgeting tends to increase over time during respiratory gas exchange measurement and fidgeting increases energy expenditure. The effect is seen with ingestion of a single large bolus of water, but if the same amount of water is taken in 3 hours the effect is not likely to be seen.

 

The speculation from the authors that the cumulative effects of this small increase in REE could translate into long-term weight loss is probably a long way beyond what might reasonably be concluded from their results. Nevertheless, even a small effect may be important, so further research to evaluate this effect is required.

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Abstract   [button text=”View at PubMed” url=”http://www.ncbi.nlm.nih.gov/pubmed/21750519″ target=”_blank” color=”blue”][/button]

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BACKGROUND:

It was previously demonstrated that drinking water significantly elevates the resting energy expenditure (REE) in adults, and that low water intake is associated with obesity and lesser success in weight reduction. This study addressed the potential of water drinking to increase the REE in children, as an additional tool for weight management.

OBJECTIVE:

To examine the effect of drinking water on the REE of overweight children.

DESIGN:

A total of 21 overweight, otherwise-healthy children (age 9.9±1.4 years, 11 males) drank 10 ml kg(-1) cold water (4 °C). REE was measured before and after water ingestion, for 66 min. The main outcome measure was the change in mean REE from baseline values.

RESULTS:

Immediately after drinking water, there was a transient decrease in REE, from a baseline value of 3.32±1.15 kilojoule (kJ) per min to 2.56±0.66 kJ per min at minute 3 (P=0.005). A subsequent rise in REE was then observed, which was significantly higher than baseline after 24 min (3.89±0.78 kJ/min (P=0.021)), and at most time points thereafter. Maximal mean REE values were seen at 57 min after water drinking (4.16±1.43 kJ per min (P=0.004)), which were 25% higher than baseline. REE was significantly correlated with age, height, weight and fat-free mass; the correlations with maximal REE values after water drinking were stronger than with baseline REE values.

CONCLUSIONS:

This study demonstrated an increase of up to 25% in REE following the drinking of 10 ml kg(-1) of cold water in overweight children, lasting for over 40 min. Consuming the recommended daily amount of water for children could result in an energy expenditure equivalent to an additional weight loss of about 1.2 kg per year. These findings reinforce the concept of water-induced REE elevation shown in adults, suggesting that water drinking could assist overweight children in weight loss or maintenance, and may warrant emphasis in dietary guidelines against the obesity epidemic.

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