Trying to lose weight? Increasing daily water intake does not really help

The claim is that water helps burn calories and reduce appetite, which in turn leads to weight loss. But there’s little evidence to support this.

Aug 23, 2023 - 00:30

Trying to lose weight? Increasing daily water intake does not really help

It’s often claimed that if you’re trying to lose weight, one of the things you should do each day is drink plenty of water – with some internet advice even suggesting this should be as much as a gallon (about 4.5 litres). The claim is that water helps burn calories and reduce appetite, which in turn leads to weight loss.

But while we all might wish it was this easy to lose weight, unfortunately there’s little evidence to back up these claims.

Myth 1: water helps burn calories

One small study, of 14 young adults, found drinking 500ml of water increased resting energy expenditure (the amount of calories our body burns before exercise) by about 24%.

While this may sound great, this effect only lasted an hour. And this wouldn’t translate to a big difference at all. For an average 70kg adult, they would only use an additional 20 calories – a quarter of a biscuit – for every 500ml of water they drank.

Another study of eight young adults only saw an increase in energy expenditure when the water was fridge cold – reporting a very modest 4% increase in calories burned. This may be because the body needs to use more energy in order to bring the...