Probing Question: Why is it so hard to lose weight?

If you're an adult American, chances are pretty good that at one time or another you've tried to diet. Chances are also good that, despite your efforts, you've found yourself standing on a scale and looking at a certain number with frustration and disbelief. It's the same number as last week, and the week before, even though you've been cutting back on sweets and going to the gym an extra day. Why won't that bulge budge?

"I tell my patients losing weight is the hardest thing to do, even harder than quitting smoking. Smokers can stop buying cigarettes, but you can't stop eating," says Jennifer Kraschnewski, MD, MPH, a weight loss specialist at Penn State Hershey Medical Center.

plate with large burger and fries

Americans have become notoriously bad at judging portion size, says weight loss specialist Jennifer Kraschnewski, MD, MPH.

Over two-thirds of adults in the U.S. are considered overweight or obese, according to recent reports from the government's Centers for Disease Control and Prevention. Many of those people have tried losing weight more than once, says Kraschnewski, citing several common obstacles that tend to stop people from losing weight.

One problem is that "too many people count on a ‘magic bullet,’" Kraschnewski says. Beware fad diets and weight loss pills, she adds. They often don't deliver what they promise, and even when they do, the loss can't be maintained once the intervention ends. "Even weight-loss surgery has a risk of weight regain if the person fails to follow through with lifestyle changes."

"The simplest 'equation' for weight loss is to eat fewer calories than you burn," explains Kraschnewski, but Americans have become notoriously bad at judging portion size and therefore don't have an accurate sense of how many calories they're consuming. In our super-sized fast food culture, a single "deluxe" burger and large shake can exceed 2,000 calories, the equivalent of an entire day's caloric needs for many people.

Even when people get it right, too often success doesn't last, Kraschnewski notes. "People forget they need to keep up those habits. Weight loss really involves persistence. It means a permanent lifestyle change."

Kraschnewski and colleagues recently analyzed eight years' worth of body weight data for U.S. adults collected by the National Health and Nutrition Examination Survey. In their findings, they identified groups of people who were successful in maintaining weight loss for at least a year.

They then worked with a group of sixty-one people who were successful to determine what that group was doing right; those findings will appear in an upcoming issue of Qualitative Health Research. Kraschnewski and colleagues identified thirty-six weight control tactics that successful individuals used, categorized in five areas: nutrition, exercise, restraint, self-monitoring, and motivation. Many of these tactics are intuitive, she notes, but may be useful to help others achieve at losing weight and keeping it off. Successful tactics included exercising with friends, looking for information on weight loss and nutrition, and allowing oneself a small amount of unhealthy food.

"No one weight loss plan works for everyone," says Kraschnewski, "though the Mediterranean diet, which emphasizes fresh fruits and vegetables and minimizes red meat consumption, has been shown to contribute to better cardiovascular health and lower rates of Alzheimer's in addition to helping with weight loss. Any amount of weight loss will be important for someone in the higher ranges of the body mass index."

Kraschnewski believes that by studying weight loss successes, she and her colleagues may have some empirical data to help them guide clients toward success. So if you find yourself fighting the battle of the bulge yourself, don't despair, she urges. Others have succeeded, and you can, too.

Last Updated November 02, 2010