It's official - stress makes you fat

[Dodger]

Australian scientists have discovered why stress can make us fat.

New research published in an international journal has revealed that chronic stress triggers the body's fat cells to grow and multiply.

The link between stress and obesity has been known for more than a decade but these findings are the first to explain how exactly the connection works.

The research by Australian, US and Slovakian scientists could lead to new therapies that shrink fat cells or make them die.

Professor Herbert Herzog, director of neuroscience at the Sydney's Garvan Institute of Medical Research, said he expected the findings to have a profound effect on the way society deals with the obesity epidemic.

The research team made its discovery by feeding stressed and unstressed mice a "comfort food" diet high in fat and sugar.

The stressed mice gained twice as much fat as unstressed mice, because the stress caused fat to be stored differently.

Prof Herzog said a molecule called neuropeptide Y, released by the body when stressed, appeared to unlock receptors in the body's fat cells, stimulating the cells to grow in size and number.

This same mechanism was expected in humans.

While the stress reaction was normal and unavoidable, scientists are working to block the dangerous knock-on fat reaction that it triggers.

"If we can interfere before it causes fat to amass, it could have a major impact on cardiovascular disease, diabetes, and cancer which all have links with obesity," Prof Herzog said.

Study leader Professor Zofia Zukowska, of Georgetown University, said they also hoped to be able to target obesity directly.

"We may be able to reverse or prevent obesity caused by stress and diet, including the worst kind of obesity - the apple-shaped type," Prof Zukowska said.

The findings were published on Monday in the journal Nature Medicine.

http://www.theage.com.au/news/National/Its-official--stress-makes-you-fat/2007/07/02/1183351105088.html

[Samuel]

http://seattletimes.nwsource.com/html/nationworld/2003770752_fat02.html

Monday, July 2, 2007 - Page updated at 02:03 AM
Scientists discover stress-obesity switch
By Rob Stein
The Washington Post

WASHINGTON — Scientists reported Sunday that they have uncovered a biological switch by which stress can promote obesity, a discovery that could help explain the world's growing weight problem and lead to new ways to melt flab and manipulate fat for cosmetic purposes.

In a series of experiments on mice, researchers showed that the neurochemical pathway they identified promotes fat growth in chronically stressed animals that eat the equivalent of a junk-food diet.

The international team also showed that blocking those signals can prevent fat accumulation and shrink fat deposits, while stimulating the pathway can strategically create new ones, possibly offering new ways to remove fat as well as to mold youthful faces, firmer buttocks and bigger breasts.

"It's very exciting," said Zofia Zukowska of Georgetown University, who led the research published online by the journal Nature Medicine. "This could be revolutionary."

While cautioning that the safety and effectiveness of the approach remains to be proven in people, other researchers said the findings reveal new clues about the basic biology of fat and why obesity has been increasing so quickly, particularly in Western countries.

"There is a lot of uncontrollable stress right now in our societies. There's also a lot of inexpensive high-fat food," said Mary Dallman of the University of California, San Francisco, who co-wrote a commentary accompanying the research. "This could help explain the obesity epidemic."

The researchers have applied for a patent and begun negotiating with drug companies to license the technology. They predicted studies in people could begin within two years.

Previous studies have indicated that while acute stress can make some people lose weight, chronic stress, such as long-term job insecurity, might cause some to put on pounds.

To explore this, Zukowska and her colleagues subjected mice to chronic stress — either standing in cold water an hour a day or being caged with a more aggressive alpha mouse for 10 minutes a day — and then gave them standard feed or a high-fat, high-sugar diet similar to the junk-food fare that many people consume.

"By treating the mice the way humans are treated, which is introducing a chronic stress from which they cannot escape and introducing this abundance of food, we mimicked what happens in American society," Zukowska said.

After two weeks, only the mice that were both stressed and fed the junk-food diet gained a significant amount of weight, accumulating about twice as much fat in their bellies as non-stressed mice that consumed the same diet.


"This tells me it's not just the stress. It's the combination of stress and the high-fat, high-sugary rich diet ... There is some kind of interaction going on."

Moreover, the stressed-out junk-food eaters put on the worst kind of fat — deposited around their abdomens and laced with hormones and other chemical signals that promote illness. After three months, the animals developed the constellation of health problems obese humans often get: high blood pressure, early diabetes and high cholesterol.

When the researchers examined the animals' fat tissue, they discovered sharply elevated concentrations of a substance called neuropeptide Y (NPY), a chemical messenger produced by the nervous system. They also had far higher levels of a molecular partner that NPY needs to work, known as the neuropeptide Y2R receptor.

NPY induces the growth of immature fat cells, coaxes mature fat cells to get bigger, and promotes blood vessels necessary to sustain fat tissue.

Scientists also showed injecting a substance that blocks NPY prevented mice from accumulating fat even if they were stressed and ate a high-fat diet, and could shrink fat deposits by 40 percent to 50 percent within two weeks.

The technique could offer an alternative or supplement to liposuction, Zukowska said.

On the flip side, when the researchers inserted pellets containing NPY under the skin of mice and three monkeys, they were able to stimulate localized fat growth, suggesting the approach could replace skin fillers and other cosmetic and reconstructive surgical techniques.

"This has tremendous potential applications for both cosmetic and reconstructive surgery," said Stephen Baker, a Georgetown professor of plastic surgery who helped conduct the research.

Others cautioned that much more research would be needed to confirm that the same system works in people, and to learn whether blocking or stimulating NPY receptors is safe.

And they warned that it is unlikely that anything will ever be a panacea for weight gain or replace eating well and exercising regularly.

"I wouldn't want people to not to make an effort to control their weight or lose weight while waiting for this magical solution to fix the whole thing," said Louis Aronne of the Weill Medical College of Cornell University. "This is very promising, but the average person shouldn't say, 'I can eat whatever I want and wait for that shot to take it all away.' "

[pennink]

poor little mice... having to join the 'rat race'

I KNOW stress leads to stupid choices. It's so much easier to lose weight when you're not stressed too... and if you lose weight, it's easier to deal with the stress you have!

[LC_Dave]

Oh so that's why stress is bad - CAUSE IT MAKES YOU FAT!

Gee Wizz, stress actually kills more people and destroys more lives than being fat does!

[amberview]

I notice their combination was high sugar and high fat. I'm betting on the sugar and stress that caused the weight gain.