A review of various studies recommends to those who wanted to shed off those extra pounds to drink at least one liter of water per day.

Brenda Davy, associate professor of human nutrition, foods, and exercise in the College of Agriculture and Life Sciences at Virginia Tech, and her team of researchers reviewed all these studies.

Rebecca Muckelbauer, renowned expert in Nutrition Sciences at the Berlin School of Public Health, Charité University Hospital in Berlin, also did a similar review as people often ask her if it is possible for them to lose weight by drinking water. These inquiries convinced her to revisit all the studies related. Among 11 studies they found, three of them showed the possibility of losing weight.

In Davy’s review, they found out that that drinking two cups of water before meal may aid in the reduction of weight to up to four pounds compared to those who didn’t drink the extra water. The study was carried out on middle aged and older adults. Another study revealed that those who drank at least one liter a day also lost weight. However, the researchers were not able to explain how water was able to cut those extra pounds.

One theory that Davy had in mind was that water could kill feelings of hunger. This is not something really new as dieticians would always advise their patients to drink water first in case they feel sudden hunger then observe if they are still hungry.

Muckelbauer suggested another theory which is called "water-induced thermogenesis." Thermogenesis is the process of heat production which will then be released into form of energy. Drinking water makes a person more energetic.

The idea is that "drinking water itself increases energy expenditure of your body. It has an energy consuming effect. This is not very well studied," Muckelbauer told Reuters Health.

She also pointed out that in one survey they found, not all who drinks more water were slimmer citing that obese people actually drinks more water than those with normal weight.
Both researchers suggest that further research must be done to create a strong link of between water and weight loss.