Obesity is a growing health concern in the US, affecting more than a third of American adults. But according to a new study, losing weight does not have to be a mammoth task; simply drinking 500 ml of water 30 minutes before each meal can help.

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Drinking 500 ml of water half an hour before breakfast, lunch and dinner may help with weight loss, according to new research.

Published in the journal Obesity, the study found drinking 500 ml of water half an hour before eating breakfast, lunch and dinner led to greater weight loss among obese adults compared with those who did not drink water before mealtimes.

“The beauty of these findings is in the simplicity. Just drinking a pint of water, three times a day, before your main meals may help reduce your weight,” says Dr. Helen Parretti, of the University of Birmingham in the UK.

It is well established that water is essential for our health. It rids toxins from the body, transports nutrients and oxygen to cells, lubricates joints, regulates body temperature and protects the body’s organs and tissues, among other functions.

Previous studies have also demonstrated other benefits for water consumption. In 2013, for example, Medical News Today reported on a study suggesting that drinking water before a mental task can boost brain performance.

Other research has also suggested water consumption may be effective for weight loss. Dr. Parretti and colleagues set out to investigate this association further.

The team enrolled 84 obese adults to their study and randomized them to one of two groups. One group was required to consume 500 ml of tap water 30 minutes before breakfast, lunch and dinner – referred to as “preloading” – every day for 12 weeks. The remaining participants – the control group – were asked to imagine their stomach was full prior to each main meal.

All participants received a weight management consultation at study baseline, in which they received advice on how to improve their diet and physical activity levels. All subjects also received a follow-up telephone consultation 2 weeks later.

Compared with the control group, participants who preloaded with water prior to each main meal lost an average of 1.3 kg (2.87 Ibs) more in weight. Preloading subjects lost an average of 4.3 kg (9.48 Ibs) over the 12-week period, while control subjects only lost an average of 0.8 kg (1.76 Ibs).

Dr. Parretti told MNT that the study was not designed to understand exactly how water consumption drives weight loss, but she suggested several possible mechanisms could explain the findings.

“These could include that drinking water increases your metabolic rate temporarily or that it makes you feel fuller so you then eat less at mealtimes,” she noted.

The researchers say their findings provide “preliminary evidence” that drinking water prior to main meals can aid weight loss, and note that it is a simple strategy health care professionals could easily promote for overweight or obese patients.

Dr. Parretti adds:

When combined with brief instructions on how to increase your amount of physical activity and on a healthy diet, this seems to help people to achieve some extra weight loss – at a moderate and healthy rate. It’s something that doesn’t take much work to integrate into our busy everyday lives.”

Dr. Paretti told MNT, however, that there are some groups of patients, such as those with heart or kidney failure, for whom consuming a pint of water before mealtimes may not be appropriate.

The team now plans to conduct a larger, longer-term trial looking to gain a better understanding of how water preloading influences weight loss.

“Losing a few extra pounds over the course of a year can be significant to an individual, and this could be an easy way to help with that weight loss,” says Dr. Parretti. “It’s a simple message that has the potential to make a real contribution to public health.”

In March, a Spotlight feature from MNT looked at why drinking water is important for our health.