Eating fast makes you fat as your brain doesn't know you're full

Published on Tuesday 21 October 2008 23:08

EATING quickly until you feel full trebles your chance of being fat, according to new research.

The study, published today in the British Medical Journal, blames access to inexpensive food in large portions and fast food for the global obesity epidemic.

The researchers claim that, until the last decade or so, most adults did not have the opportunity to consume enough calories to enable fat to be stored.

However, with changing eating habits, people are eating high-calorie foods too quickly for the body to suppress the appetite in time to stop overeating.

Researchers from Japan and Australia recruited more than 3,000 Japanese men and women aged 30 to 69 between 2003 and 2006. Participants were sent a diet history questionnaire about their eating habits, which included questions about eating until full and their speed of eating.

Around half, 50.9 per cent, of the men and 58.4 per cent of the women said they ate until they were full. And just under half, 45.6 per cent, of men and 36 per cent of women said they ate quickly.

The group of participants who said they ate "until full and ate quickly" had a higher body mass index (BMI) and total calorie intake than those who did not "eat until full and did not eat quickly".

The researchers also found both men and women in the "eating until full and eating quickly" group were three times more likely to be overweight than the participants from the "not eating until full and not eating quickly" group.

Professor Hiroyasu Iso, from Osaka University, explained the human body has a feedback system which takes several minutes to register food with the brain. Eating too quickly means the body can consume more calories than it requires before the brain feels fed and suppresses the appetite.

He said: "Eating slow would give the brain time to recognise enough food has been eaten."

The authors recommend doctors advise parents to encourage children to eat slowly, serve appropriate portion sizes, and eat as a family in a non-distracting environment.

Carina Norris, a nutritionist, said eating more slowly could help overweight people shed pounds and that the problem was that many people in today's society eat while on the move.

She said: "They eat their meals too quickly so they generally carry on eating beyond the amount the actually need. Effectively, they don't reach the point where the brain registers that they have had sufficient food.

"It is the way our lives are now – if you don't rush meals it would give you time for these signals to reach your brain and you would feel fuller earlier rather than just keep eating."

BACKGROUND

A MAJOR international report last year revealed Scotland is the second fattest nation in the world, behind only the United States.

More than a quarter of adults in Scotland are classed as obese.

The findings led officials to describe the problem as an "obesity epidemic", which they said was costing Scotland 171 million a year.

The Scottish Government has introduced new regulations which restrict the amount of deep fried food, such as chips, which can be served to pupils.