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Thursday, 29 June, 2000, 02:38 GMT 03:38 UK
Brain 'delay' leads to obesity
Obesity
Obesity is a growing problem among Europeans
It takes 10 minutes before the brain realises that the body has taken in enough food, according to scientists.

A study carried out at the University of Florida found that the delay in eating and realising that you are full can lead some people to gorge themselves.

It also reports that the delay is longer in obese people than it is in those who are lean.

The scientists suggest the findings could help to improve the diagnosis and treatment of obesity and other eating disorders.

They examined brain activities among 18 participants. These people fasted for 12 hours and then underwent continuous brain scanning for 48 minutes.

Using a technique called functional magnetic resonance imaging (fMRI), the researchers were able to record the brain's activity in response to internal and external stimuli such as eating and drinking.

Ten minutes after the scanning began, participants were given a water solution containing dextrose, a type of sugar.

The researchers detected two peaks in brain response after the water solution was taken.

The first occurred about 90 seconds afterwards and was, the scientists said, related to swallowing and other aspects of the eating process.

The second, more important and sustained peak began about 10 minutes after the ingestion and was the brain's signal that it was physically full.



It bolsters the long-standing adage: 'don't gobble your food'

Dr Peter Fox, University of Texas
The peak lasted about two minutes and corresponded directly with an increase in sugar and insulin levels in the blood.

The scientists also identified that the brain changes occurred in the hypothalamus, a portion of the brain which is responsible for regulating body temperature and metabolism.

"The hypothalamus has been known for many years as being related to the regulation of eating," said Yijun Liu, assistant professor at the University of Florida's department of psychiatry.

"But this is the first study in humans able to directly demonstrate that it undergoes dynamic and physiological changes as a result."

He said the findings may help to develop new drugs to treat obesity and obesity-related diabetes.

Dr Peter Fox, from the University of Texas who was part of the research team, added: "It bolster's the long-standing adage: 'don't gobble your food'.

"Eating slowly may provide more time for the feeling of fulness to occur, especially in the obese, whose fullness signals are slower and weaker."

'Exciting'

Dr Wendy Doyle, spokeswoman for the British Dietetic Association, described the study as "exciting".

However, she said more research was needed to see if the findings applied to the digestion of food.

"I have some reservations about the study. It involved participants taking a sugar-based drink and this is not the same as food.

"If the same was done with carbohydrates as opposed to a sugar drink then it may have greater significance. I am sure that is what the researchers intend to do."

The research is published in the latest issue of Nature magazine.

Obesity among children in the US is already well documented, but recent research suggests the problem is spreading throughout Europe.

Obesity is linked to diabetes, heart disease and cancer in later life - and there is already anecdotal evidence of cases among younger people.

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