Obesity a growing problem in US
Published 12:00 am Thursday, March 22, 2012
By Katie Scarvey
KANNAPOLIS – When Dr. Andrew Swick noted recently that we have an epidemic of obesity in this country, it’s unlikely that anyone in his audience was surprised.
But what was startling was his pronouncement that the problem of overnutrition (which causes obesity) is now a bigger problem, worldwide, than undernutrition.
In China for example, researchers estimate that by 2015, obesity rates will double from 2005 rates.
Swick spoke Feb. 28 as part of the Appetite for Life series at the NC Research Campus, hosted by the UNC Nutrition Research Institute.
Since 2010, Swick has been the director of obesity and eating disorders research at the UNC Nutrition Research Institute and has been doing obesity research since the 1980s.
Swick explained the fattening of America with a series of slides from the Centers for Disease Control showing, with a map of the United States, how obesity rates have surged in the past 25 years.
Swick noted that CDC figures show that there are many states now with more than 30 percent of adults classified as obese. (As of 2010, 27.8 percent of North Carolina adults were considered obese.)
With obesity — as defined by a body mass index, or BMI, of 30 or higher — comes an increased risk for disease and death.
Today, three times as many children are obese than they were in 1980, a fact that is “striking and important,” Swick says. Children are also getting obese at younger ages.
Increased riskfor diabetes
Obesity, Swick said, is a risk factor for diabetes, metabolic diseases, hypertension, pulmonary diseases, asthma, osteoarthritis and sleep apnea.
Swick said that 90 percent of those with type 2 diabetes are obese or overweight — and he also noted that there are states in which 10 percent of the population has diabetes. (The CDC figures for 2008 estimate that 10.8 percent of Rowan County adults had type 2 diabetes.)
There is also an increasing body of evidence that obesity is a risk factor for cancer. A woman has a 3.5 times greater risk of getting endometrial cancer, for example, if she is obese, Swick said. In fact, more than half of endometrial cancers are believed to be the result of obesity and overweight. Obesity is also associated with higher rates of colon cancer and esophageal cancer.
“We’re trying to understand how obesity leads to these conditions,” Swick says.
Researchers know that there is an increase in inflammation with obesity, and now they’re theorizing that inflammation is largely due to excess adipose tissue, Swick said.
For many years, scientists believed that adipose tissue was simply storage for fat.
“Now we know that adipose tissue produces hormones that regulate other aspects of metabolism. Leptin, for example, is produced by fat cells, and leptin is associated with increased cancer cell growth and contributes to the development of cancer,” he said.
It’s obvious that people suffer physically from obesity, but the condition takes a staggering toll economically as well. Swick noted that in the U.S., it can cost up to $8,000 per person a year — and costs us as a country $450 billion a year, with $160 billion in direct medical costs.
Leading causeof preventable death
Obesity — which has recently surpassed cigarette smoking as the leading cause of preventable death in the U.S. — accounts for 12-13 percent of all medical costs, Swick said.
The good news, Swick said, is that while losing a large amount of weight may seem overwhelming to people, even modest weight loss of 5-10 percent can significantly improve overall health.
“You don’t have to get down to your high school weight to see the benefits,” he said.
The equation for weight loss is a simple one.
“If you eat more calories than you burn off, you’ll gain weight.” And conversely, of course, if you eat fewer calories than you burn off, you’ll lose weight.
An imbalance in the equation by even 1 percent can mean a weight gain of 40 pounds in a 20-year period.
It’s easy then, Swick acknowledged, to gain weight.
Swick gave an example. If a 120-pound woman overeats by 100 calories per day — which isn’t much, he noted — she could gain 100 pounds in 10 years.
Losing weight is a constant challenge, he said, because the body is trying to maintain the weight it had before. And exercise, while beneficial, can also stoke the appetite.
We used to have to work to get food, and overeating wasn’t typically a problem. Now, we “hunt in our car and forage on the shelves and drive back home,” he said.
“We’re not exercising, we’re not working to get our food, and it’s too plentiful.”
Most women need around 2,000 calories a day, while men’s needs are somewhat higher, around 2,400-2,600.
But there is “tremendous variability” among people, driven by genetics and other things.
“Even for people with the same lean body mass, requirements can vary between 200-300 calories,” he said.
Things get complicated when you realize that “many organs in the body contribute to hunger signals,” Swick said.
The brain does have a prominent role, he acknowledged, but “sensors throughout the body regulate and signal the hunger, satiety and energy expenditure.”
Researchers are taking a much harder look at the gut, which is much more complex than previously thought. How fat is metabolized in the intestine has an effect on our food intake, for example. Animal studies have shown that gut microbes probably play some role in body weight regulation, Swick said, in terms of how much food gets absorbed.
Genetics and environment both have a role to play in the obesity problem. There are up to 6,000 genes involved in regulating body weight.
But the relatively short period of time in which obesity rates have skyrocketed can’t be explained by genes, Swick acknowledged, since the genetic blueprint can’t change that quickly.
It’s also not just humans who are getting bigger, Swick said. Animals are getting larger as well, including domestic animals, feral animals and lab animals.
One change worth noting is that 63 percent of our total calories are now coming from processed food, Swick says, a large increase from what it used to be. That means people are eating more refined carbohydrates than ever before.
Chemicals in our environment may also be playing some role in obesity, he noted. Lack of sleep can also correlate to increased BMI.
Ultimately, there are many factors in obesity, Swick said. But at the end of the day, the causes don’t matter. What matters is that each of us finds a way to balance our own personal energy equation.