How coffee could be the secret to fighting obesity

Drinking coffee could help people slim down and avoid type 2 diabetes by helping the body burn off extra calories, according to researchers.

A cup of the hot drink could kick-start someone’s brown fat into action, they said –brown fat is active tissue which burns sugar and fat from food to warm up the body. 

This is different to white fat, which is what makes people look overweight. This is food fat stored by the body when people eat more energy than they use.

Caffeine is believed to be the part of coffee which takes the body’s calorie-burning up a gear, but the scientists said more research is needed.

More than two thirds of UK adults are overweight and around 3.4million people – one in 20 – have type 2 diabetes, which can lead to a stroke or heart disease. 

Researchers from the University of Nottingham tested their theory on nine healthy volunteers after finding it had worked in a lab.

The people were aged 27, on average, and had to refrain from exercising, drinking caffeine or taking drugs or alcohol for nine hours before the tests.

They were then given a cup of Nescafé instant coffee, or water in an experiment for comparison, and their body scanned while the caffeine effects set in.

‘From our previous work, we knew that brown fat is mainly located in the neck region,’ said Professor Michael Symonds.

‘So we were able to image someone straight after they had a drink to see if the brown fat got hotter.

‘The results were positive and we now need to ascertain that caffeine as one of the ingredients in the coffee is acting as the stimulus or if there’s another component helping with the activation of brown fat.’

The thermal scans showed the people’s brown fat in their neck got hotter when they drank the coffee, showing it was working to burn calories.

Until now, the scientists said, nobody had found an easy and safe way to stimulate brown fat into action.

It was not clear from the research whether a single cup of coffee in the morning would be enough to trigger the calorie-burning all day, or whether people should drink it more regularly.

The researchers wrote, however, that caffeine could trigger fat-burning ‘at doses compatible with human use’.

Unlike white fat, a visible build-up of which is the result of eating too many calories, brown fat is a functioning tissue which serves to heat up the body by burning fuel – it is found in large amounts in babies and hibernating animals such as bears. 

Brown fat is perhaps confusingly named and is actually found in larger amounts in slim people. 

It is also more common in youth – it makes up around five per cent of a baby’s body mass but it was thought to disappear before adulthood. Scientists recently discovered that adults do retain small stores of it, mostly around their necks. 

‘This is the first study in humans to show that something like a cup of coffee can have a direct effect on our brown fat functions,’ Professor Symonds said.

‘The potential implications of our results are pretty big, as obesity is a major health concern for society and we also have a growing diabetes epidemic and brown fat could potentially be part of the solution in tackling them.’

The team also found that when brown fat was activated the body did a better job of controlling amounts of sugar and fat circulating in the blood.

This improvement of blood glucose control could help to protect people against type 2 diabetes, which affects around 90 per cent of the more than 3.8million people in the UK with diabetes.

Professor Symonds and his colleagues will continue their work to find out whether other sources of caffeine could have the same benefits.

Their research was published in the journal Nature: Scientific Reports.