Replacing a beer with a glass of water every day could cut people’s chances of becoming obese by 20% on average, according to a study. Researchers from the University of Navarra in Spain found that the same holds true for sugary soft drinks – having a water each day instead cut the risk of obesity among more than 16,000 participants in the study by 15%.

The study, the results of which were presented at the European Congress on Obesity in Porto, Portugal, used mathematical modelling to calculate the impact of changing the drinking habits of university graduates. Exchanging water for beer or sugary soft drinks such as colas reduced the likelihood that they would become obese. Swapping wine for water did not have an effect.

Some experts say the fattening effects of beer, which in bottles or pints usually contains more calories than a small glass of wine, are under-recognised. “Alcohol is incredibly calorific, second only to fat,” said Paul Christiansen, a researcher on addiction and obesity from Liverpool University. “And beer is one of the most calorific ways you can consume alcohol.”

Not only is beer high in calories – 142 calories in a 330ml bottle or 193 in a pint of Newcastle Brown – but people who drink alcohol also eat more. “When people consume large amounts of alcohol, that’s when they go and eat takeaways,” said Christiansen. “Nobody goes out and says, ‘I really want a doner kebab’ when you have already had a day’s amount of calories.”

When people are dieting, they check the calories in food, but they are less likely to do so for alcoholic drinks. And they have trouble sticking to a good diet when they have been drinking, he said. “It takes away people’s ability to regulate their eating,” he said.

The UK, which has one of the highest obesity rates in the world, also has one of the biggest drinking populations. Figures from a World Health Organisation report showed that in 2016 the average person from the UK drank almost double the global average. Britons last year drank the equivalent of an average of 12.3 litres of pure alcohol, while the global average was 6.4 litres.

The study gathered data from the SUN Cohort (Seguimiento Universidad de Navarra), which began recruiting Spanish university students in 1999. They filled out questionnaires on the frequency with which they drank 17 different beverages when they joined the study and were asked again every two years.



Over the course of more than eight years, 873 participants became obese. Mathematical modelling was used to calculate the difference in outcomes if people had drunk daily water instead of daily beer, wine or other drinks. The researchers adjusted for confounding factors including age, sex, physical activity, family history of obesity, and eating snacks between meals.