Previous studies have indicated that whereas 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 many consume.
After two weeks, only the mice that were both stressed and fed the junk-food diet gained a significant amount of weight. They accumulated 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 -- that is the humongous combo. There is some kind of interaction going on," Zukowska said.
Moreover, the stressed-out junk-food eaters put on the worst kind of fat -- deposited around the abdomen and laced with hormones and other chemical signals that promote illness. After three months, the animals became obese and developed the constellation of health problems that obese humans often get -- high blood pressure, early diabetes, high cholesterol -- an increasingly common condition known as metabolic syndrome.
"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.
I have had a suspicion for a long time that a certain segment of society is vulnerable to obesity due to stress and our fast-food diet (documented in the Morgan Spurlock movie Supersize Me). We have always had fat and skinny people, and I have never believed that you could only pin the obesity problem in America to one cause (eating too much, not exercising enough, etc); genetics plays a part.
Now we have another factor to look at: chronic stress. Americans spend all their time working to pay off debt and buying stuff that they think will make them happy. We take too little time off for vacations to enjoy life (and employers don't offer it). I think that the health problems that Americans suffer from are related to the factors of working too much, being too concerned with the acquisition of material goods, lack of proper medical attention (because of a lack of access to medical care) and an unhealthy sedentary lifestyle (partly fueled by too much stress from overwork).
A group called Take Back Your Time is trying to bring an awareness to this problem. Their website lists some factors:
Millions of Americans are overworked, over-scheduled and just plain stressed out.
* We're putting in longer hours on the job now than we did in the 1950s, despite promises of a coming age of leisure before the year 2000.
* In fact, we're working more than medieval peasants did, and more than the citizens of any other industrial country.
* Mandatory overtime is at near record levels, in spite of a recession.
* On average, we work nearly nine full weeks (350 hours) LONGER per year than our peers in Western Europe do.
* Working Americans average a little over two weeks of vacation per year, while Europeans average five to six weeks. Many of us (including 37% of women earning less than $40,000 per year) get no paid vacation at all.
Contemporary Americans complain of unprecedented levels of busyness in everyday life. They worry about frenetic schedules, hurried children, couples with no time together, families who rarely eat meals together, and an onslaught of "hidden work" from proliferating emails, junk mail, and telemarketing calls.
Michael Moore also touched on this in SiCKO.
The problems that Americans are facing are related to our values. We need to become more concerned with living the good life than acquiring possessions. That will require a complete reorganizing of our business and working priorities.
The bankruptcy epidemic in America can be traced to these two main causes: lack of a taxpayer-financed health care system and a value system that tells us to work to acquire possessions rather than working to enjoy the time we have on this earth. If we can find the will to change our priorities, we can solve both the health and financial problems in this country.