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Mon 29 Mar, 2010 01:26 am
We didn't evolve to survive under these conditions = We have evolved, yes, but we didn't evolve to live under these conditions ? But what are "these conditions"? I don't know what are "these conditions".
Context:
Pietro Cottone, a neuroscientist at Boston University, is not surprised that an excess of tasty food might "short-circuit" the brain's reward sensing system. "In western societies, we are observing a sudden increase in food availability. We didn't evolve to survive under these conditions," he says.
More context:
Paul Kenny and colleagues at the Scripps Research Institute in Jupiter, Florida, wondered if a diet rich in high-calorie, fatty food might also cause desensitisation and lead to obesity.
They used electrodes to measure the sensitivity of rats' brains to reward activity. Some ate normal rat food while others had limited or unlimited access to junk foods, tasty to both rats and humans. After 40 days, the brains of those that ate junk freely were less sensitive to reward activity than those in the other groups. They were also obese.
Compulsive eaters
To see if these rats would display compulsive eating in the face of negative consequences - a telltale sign of addiction - all the rats were taught that a flash of light led to a painful electric shock.
Rather than try to avoid the shock when the light came on, as the rats with limited or no access to junk food did, "addicted" rats just kept on eating. "We see the same thing in animals with extended access to cocaine," says Kenny. Like drug-addicted humans, the obese rats also had fewer receptors for the reward chemical dopamine.
The term "food addiction" is slowly becoming accepted in the field of psychiatry, says Jon Davis, an addiction biologist at the University of Cincinnati in Ohio.
"Once we start to consider obesity and pathological overeating as a psychiatric illness we're going to move a lot closer towards understanding how to come up with therapies or treatments," he says.
Pietro Cottone, a neuroscientist at Boston University, is not surprised that an excess of tasty food might "short-circuit" the brain's reward sensing system. "In western societies, we are observing a sudden increase in food availability. We didn't evolve to survive under these conditions," he says.
@oristarA,
Yes, you are correct, we evolved, but not to live under these conditions. The conditions are a surplus in available food, and a consequent to an addiction to overeating.
(Please note that the journalist who wrote the article, not the scientists necessarily, may have explained this poorly. Humans evolved to eat fatty foods and foods high in sugars under circumstances in which fatty and sweet foods
were not readily available. So people would eat lots of fatty and sweet foods at harvest time in the autumn, and this would help them to survive the winter when such foods were not available. Now, thanks to an improvement in our ability to produce and store such foods, and to ship them from other parts of the world, we are able to eat fatty and sweet foods at any time.)
@Setanta,
Good explaination Set
I was going to add that survival in nature is based upon stress--that is any benefit for survival is to be advantageous in times of physical peril--that is overeating in times of surplus provides benifits in times of famine.
Now in the era of few famines, the survival benefit of overeating leads to decreased survival benefit because of obesity, diabetes, and other weight related peril. Consequently in a culture derift of medicine--the ugly face of the 'fittest' arised and culls the less than 'fit' from the population.
Rap
@raprap,
Setanta's explanation rap has cobwebs on it.
Has this research anything to do with the article in this weekend's Sunday Times about the eradication of memory which is being presented by the scientists involved as beneficial, as I'm sure it must be, for people who have bad memories they can't forget?
"Less sensitive to reward activity" does have an uncanny resemblence to "less sensitive to painful activity" don't you think? That the conditioned reflex of Pavlovian science might not survive in conditions involving a diet of crap as is commonly served up to those who are looking for cheap nutrition with no inconvenience and that every morning they wake up to a brand new day with a clean slate in the noggin.
Some contributors to A2K seem to me to not be able to remember what they had said on earlier occasions. Perhaps obesity is not the only problem caused by ingesting large quantities of junk food.
Google Sunday Times for you all and scroll down. It's a mite tiresome but what scientific research isn't?
@spendius,
It's by Minette Marrin in the Comment section.
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