|Date: 07/09/2012 Time: 07:36:00 PM
Brain damage caused by fatty food might be one
reason why people who habitually over-eat find it so hard to lose weight,
scientists said on Friday.
New research suggests that saturated fat can destroy neurons in a part of
the brain that controls energy balance and appetite.
Researchers found changes to vital genes and proteins in the brains of mice
fed a high fat diet.
The effects in the hypothalamus, the brain's energy centre, indicated the
kind of damage normally caused by inflammation and blood clot strokes.
Lead scientist Lynda Williams, from the University of Aberdeen Rowett
Institute, in Scotland, said that "these changes may underlie the breakdown of
energy centers in the brain and may explain why it's so difficult for obese
people to maintain weight loss from dieting.
"Our results indicate that a high fat diet can damage the areas of the
brain that control energy balance and perpetuate the development of obesity.
"High fat and high sugar foods are energy dense foods which are highly
palatable and they are very easy to over-eat.
Our findings may also explain why some overweight people find it difficult
to diet and why weight loss after dieting is so difficult to maintain.
"We now plan to carry out further studies that will look at whether these
effects are reversible."
She pointed out that brain scan studies in the US had shown signs of
hypothalamus damage in obese individuals, suggesting that the effects seen in
mice may also occur in humans.
The hypothalamus is a small area at the base of the brain that contains
neurons which govern energy expenditure and appetite.
"This control breaks down in obesity, the system appears not to work, and
we don't really know why this happens," said Dr Williams, speaking at the
British Science Festival at the University of Aberdeen.
"In our study we found that genes and proteins change in response to a high
fat diet and that these changes are normally associated with damage to the
brain, indicating that damage had occurred in the hypothalamus in mice that
ate a diet high in saturated fat."
The changes happened quickly, she said.
It took three days for proteins to be affected and a week for visible signs
of disruption to genes to appear.
Dr Williams acknowledged the effects might be exaggerated in mice whose
diet was drastically altered so they obtained 60 percent of their energy from
The results did not mean people having the occasional unhealthy treat
risked damaging their brains, she said.
"The key is to avoid excessive weight gain and to eat sensibly in the first
place," she added.
"We all deserve a treat now and then."
Another study presented at the meeting showed how the way snacks are
presented in cafes can alter people's eating habits. Pictures of healthy, less
healthy, and unhealthy items were arranged in a line beneath the number of
calories each contained.
The healthiest foods, such as fruit and cereal bars, were on the left and
the unhealthiest, such as chocolate and cake, on the right.
A message read: "If you want to consume fewer calories today then choose a
snack from the left."
Tested in two coffee shops, the sign led people to reduce the energy value
of snacks they bought by about 66 calories on average.
Psychologist Dr Julia Allan, from the University of Aberdeen, said: "We're
very excited by this.
Research from the US has shown that if you consistently reduce calorie
intake by about 100 calories that can lead to weight loss."