A British researcher returns to the misconceptions that circulate on the fact that drinking water can help lose weight.
- By drinking plenty of water daily, the net increase in calories burned is minimal.
- Water may have an appetite suppressant effect, but it does not lead to long-term weight change.
- It does not really satiate us, because it is a liquid that is quickly evacuated from the stomach.
We often hear that to lose weight, you need to drink plenty of water every day. On social networks, especially on Tiktok, some even argue that drinking 4.5 liters of water a day would help you lose weight and relieve digestion problems. The idea is that water helps burn calories and reduce appetite, which leads to weight loss. However, in a publication by The ConversationDuane Mellor, a researcher from Aston University (England), indicates that there is little evidence to support these claims.
Hydration and weight loss: a minimal increase in calories burned
A search, conducted with 14 young adults, showed that drinking 500ml of water increased resting energy expenditure (the amount of calories our body burns before exercise) by around 24%. However, this effect only lasted for an hour. Another study found a very modest 4% increase in energy expenditure only when the water was cold. These results suggest that the effect of water on energy expenditure is limited and short-lived, calling into question its effectiveness for long-term weight loss. “This work focused on healthy young adults. Further research is needed to determine whether this effect is also seen in other groups (such as middle-aged adults and older adults),” says Duane Mellor.
The limited effects of hydration on appetite
Although several studies have shown that drinking water with meals can reduce appetite, it seems that this effect varies according to age. A study showed that middle-aged and older adults lost 2 kg over a 12-week period when they drank water before meals. In contrast, younger participants (aged 21 to 35) did not lose weight. “So while water may have an appetite suppressant effect, it does not appear to cause long-term weight change and may be due to conscious changes to your diet.”
Water, a liquid evacuated quickly by the stomach
Drinking only water is not enough to lose weight significantly. According to the explanations of the British researcher, water is a liquid that is quickly evacuated from the stomach, which means that it does not really fill us. “More interestingly, due to the shape of the stomach, liquids can bypass any semi-solid food contents being digested in the lower part of the stomach. This means that water can still be quickly drained from the stomach.” However, work has shown that water mixed with other substances, such as fiber, soups or vegetable sauces, can delay the rate at which the stomach empties of its contents, which means that the you can feel full longer.