Can water or diet drinks aid weight loss?

“Drinking water can help dieters lose at least five per cent of their bodyweight,” the Metro has reported.

The story is based on research that hoped to find evidence to support the common sense theory that replacing high calorie drinks with water or diet drinks helps weight loss. While patients in all groups lost weight on average, the study failed to prove this intuitive method of weight loss was better than simply advising overweight people on how to lose weight.

The news was based on a small study of overweight or obese adults, which looked at whether encouraging them to drink water or diet drinks rather than sugar-sweetened drinks could help with weight loss, without other dietary changes. It found that those who were encouraged to drink water lost on average 2.0% of their body weight, those on diet drinks lost 2.5% of their body weight and those in the control group lost 1.8%. The difference in weight loss between the groups was not statistically significant.

A separate analysis did find that people switching to water or diet drinks were more likely to lose 5% of their body weight, but the overall, more important findings suggest that, on average, the groups did not differ in weight loss.

It’s worth pointing out that the study was funded by a leading bottled water company in the US. It’s also noteworthy that people in the water/diet drinks groups were given the bottled water or dietary beverages. In real life, people who had to buy their own drinks might not be as good at sticking to drinking low calorie alternatives.