Penn experts weigh in on food debate

Six out of 10 of you reading this are either overweight or obese. And, like many Americans, you probably made a vow on Jan. 1 both to lose weight and to exercise more.

But, despite good intentions, Americans are not getting any skinnier. Charlene Compher, assistant professor of nutrition science in the School of Nursing, said the obesity epidemic has now been raging for two decades. Tipping the scale is not just a red, white and blue phenomenon either. “Every developed country in the world has had radical increases in their proportion of the population that has obesity,” said Compher.

You can use what the scientific community calls the body mass index—your weight in kilograms divided by the square of your height in meters—to categorize your current weight. If your BMI is more than 25, consider yourself overweight. More than 30 means you’re obese. But there’s a larger story behind these numbers. According to Philippe Szapary, a general internist and assistant professor in the School of Medicine, serious health risks go hand-in-hand with obesity. Diabetes, heart disease, hypertension, stroke, respiratory problems and the list goes on and on.

How we got there

Compher said bulging waistlines can be correlated to the deluge of high-calorie food in the American diet. French fries and hamburgers may seem like the perfect quick-fix dinner but the amount of calories hidden in these foods can be deleterious to your health. “It is a good idea to stay away from fast foods because they are so laden with calories and have limited vitamins and minerals,” advised Compher.

While a cheesesteak here and there may seem like no big deal, it does not take that many more calories eaten per day beyond what you’re expending to send you into the danger zone—200 to be exact. “Five years later, you notice your weight has gone up 6 to 7 pounds. It sneaks up on you because the caloric differential is not huge,” said Compher.

Picking up those extra calories is a cinch for those who always eat out. And this goes for all types of restaurants, not just the fast-food variety. “It’s very difficult to walk out of one of those places without having just eaten 1,000 calories by virtue of the size of the portions,” said Compher.

Several critics have even recently pinned the crisis on the USDA’s Food Guide Pyramid, which tries to instill the message that fats should be used sparingly. They argue that Americans were misled, pointing to the overconsumption of foods like fat-free cookies and low-cholesterol snacks that, while low in fat, are high in sugar and refined carbohydrates.

Some have been so unhappy with the USDA’s recommendations that they’ve come up with an entirely new food pyramid. Walter Willett at the Harvard School of Public Health recently proposed new guidelines in his Healthy Eating Pyramid, which puts exercise, whole grain foods and plant oils at the base of the pyramid but practically bans white rice, white bread and pasta.

But Compher is not ready to chuck the USDA’s guidelines in the trash. Nor does she think Willett has found the answer. “If this obesity epidemic is worldwide, which there is substantial data for, the whole world doesn’t use the USDA food guide pyramid,” she said. “There are still portions of the world where rice is still a substantial part of the diet. To tell people to eat white rice sparingly is not realistic at all.”

Food—the good, the bad, the ugly

The key to maintaining a healthy weight is something Americans have known for a long time. When mom told you to finish your vegetables and slapped your hands when you reached one too many times into the cookie jar, she was onto something. Szapary said fruits and vegetables should be consumed in abundance. He takes the “you-can-never-have-enough” approach.

Although some diet fads would have you believe that all carbohydrates are bad, Szapary said there’s a difference between good and bad carbohydrates. Bad carbohydrates are things you’d find in the vending machine, like soda, cookies, candies and cakes. Good carbohydrates are foods like fruits and vegetables, which are good sources of fiber, antioxidants and vitamins. Same goes for fats. Good fats—or polyunstaturated and monounsaturated fats—include olive oil, fish, tree nuts, flax seed and peanuts. Compher also suggests eating plenty of fiber and whole grains, which are vitamin- and mineral-rich and will help you feel fuller.

“The USDA food pyramid is sound the way it’s constructed,” said Compher. Just make sure you make better food choices and understand what a serving means.

Eating better does not have to mean going to extremes either. Compher advises caution when going on high-protein, low-carbohydrate diets like the Atkins diet. “At this point, it is do it at your own risk,” she warned. Szapary said before scientists can give a fair assessment more long-term studies—such as the one being conducted by Gary Foster, clinical director of the Weight and Eating Disorders Program, here at Penn—must be led. Szapary points out that theoretical risks of high-protein diets—like impaired kidney functions, thinning of the bones, and exercise intolerance—need to be examined.

Jumpstart your heart

Weight maintenance strategies should also have a physical activity component. Small lifestyle changes like parking your car in the farthest spot, taking the stairs instead of the elevator, and going on 10-minute walks around campus during your break will move you closer to your goal, said Compher. Szapary suggests shooting for 150 minutes a week of physical activity.

“The challenge of weight maintenance is not something that’s here today and gone tomorrow. It will be until the day you die,” said Compher. To that end, taking baby steps may bring you a lot further than jumping on the latest bandwagon.


For healthy eating according to the USDA, visit www.nal.usda.gov:8001/py/pmap.htm. The Centers for Disease Control and Prevention offers an online BMI calculator at www.cdc.gov/nccdphp/dnpa/bmi /calc-bmi.htm.

Originally published on February 13, 2003