CHAMPAIGN, Ill. - Normal weight and underweight teenage girls who falsely believe they are overweight are at significantly greater risk of succumbing to unnecessary and unsafe weight-loss behaviors than girls who can accurately assess their weight status, according to new research by a University of Illinois expert in eating disorders and body-image perception.
Janet M. Liechty, a professor of social work and of medicine at Illinois, says that body-image distortion, rather than the more commonly used measure of body dissatisfaction, may be a better screening tool to help identify non-overweight girls at risk for unsafe weight-loss practices.
"Body-image distortion appears to be a more discriminating indicator of distress than body dissatisfaction, but it's not something that's typically screened for by health-care providers," Liechty said.
"Usually, teens and their parents only get weight-related feedback from the doctor when the child is overweight. But kids of any weight can struggle with body-image, and poor body-image can negatively affect medical outcomes in ways we often don't recognize."
Childhood obesity is an important public health concern, but if the emphasis is only on children who are overweight, signs of body-image distress among normal weight kids could be overlooked, Liechty says. If left unaddressed, those problems could eventually translate into unhealthy weight-loss behaviors, disordered eating and future weight problems.
"Body-image distortion is something we can begin to screen for to identify teens at risk for unsafe weight-loss behaviors," she said.
Liechty's research, published in the Journal of Adolescent Health, examined the relationship between body-image distortion and three types of weight-loss behaviors - exercise, dieting, and extreme ways of losing weight such as laxatives, diet pills and purging.
Culling from a longitudinal sample of more than 5,000 non-overweight adolescent girls in the U.S. whose body-mass index was less than the 85th percentile, Liechty compared the teens' actual, objective weight status with what they believed their weight status to be, and looked for discrepancies. If the teens perceived themselves to be overweight when they actually were not, the discrepancy was flagged as overestimation, or body-image distortion.
To examine how overestimation of weight status affected future weight-loss behaviors, Liechty employed logistic regression analysis to predict the onset of the three types of weight-loss behaviors one year later. She discovered that body-image distortion predicts the onset of dieting, and the onset of extreme and unsafe ways to lose weight.
"What this means is, a girl with a distorted body-image is at much greater risk for resorting to unsafe dieting and extreme weight-loss methods than a girl without
body-image distortion, even if she doesn't need to lose weight," Liechty said.
This discovery highlights the importance of cultivating an accurate and positive body-image throughout the teenage years, and of being wary of dieting and extreme methods to lose weight among teens, which are somewhat of a trap, Liechty says.
"This study suggests that if otherwise healthy, non-overweight girls begin using a type of potentially unsafe weight-loss strategy, such as dieting or an extreme method, the odds that they will continue to use that method one year later increase from three to 11 times, " she said.
In other words, if a teen starts down a path of risky weight-loss practices, they're much more likely to continue using that method.
"It doesn't just fade away or stop all of a sudden," Liechty said. "That's why early detection of risk factors such as body-image distortion, and prevention of unnecessary dieting and unsafe weight-loss methods, is the key to pre-empting unhealthy behaviors. We need to educate girls and their parents that fad diets, quick-fix promises, and extreme weight-loss methods are a hoax. They don't work over the long term and they might do harm."
Compared to body dissatisfaction - which has been positively correlated with eating disorders, depression and high-risk behaviors among adolescent girls - body-image distortion may be a better red flag for unsafe weight-loss among teens.
"Body-image is often measured as body-image satisfaction, which is how satisfied you feel about your body," she said. "While that's important, the problem with using that measure is that some studies show that 50 to 80 percent of women are dissatisfied with their bodies. That kind of ubiquitous discontent doesn't give a very specific measure of body-image distress. It turns out that body-image distortion may be a more useful screening tool for counselors, parents or health-care providers."
In contrast to dieting and extreme methods of weight-loss, Liechty's research also discovered that body-image distortion has no relationship to girls' use of exercise as a primary way to lose weight, suggesting that body-image distortion motivates girls to use unsafe but not safe methods of weight control.
This is important to know, Liechty said, because exercise is a standard recommendation for healthy adolescent weight management, and it has many health benefits such as cardio-respiratory fitness and improved mood.
"Choosing a lifestyle that's sustainable and healthy - where the fuel intake matches the output - is really the safest long-term plan for weight management," Liechty said.
"Even though excessive exercise or exercise addiction can become a problem for a small percentage of people, staying physically active is an important ingredient of lifetime weight management. But if we exercise out of addiction or a punitive attitude toward our bodies, it's associated with depression and anxiety. So the attitude and the relationship with self and with body matter a lot in how we approach taking care of ourselves."
Liechty says her findings underscore the urgency for prevention efforts that foster positive and accurate body-image among adolescent girls.
"The best method of weight control is to focus on lifestyle changes and not on radical approaches, because extreme methods wreak havoc with our body chemistry as well as our attitude toward food and toward our bodies," Liechty said.
Dieting, especially what Liechty calls "teenage-style dieting," and extreme weight-loss methods can be risky business.
"They tend to be all-or-nothing, which often leads to cycles of restricting and bingeing. Ironically, other research has shown that this type of dieting among children and teens usually leads to weight gain later in life."
Learning healthy weight-loss and maintenance behaviors is important because bad habits can be addictive, leading to lifelong struggles with eating, Liechty said.
Overweight teens who desire to lose weight need support and a sensible, sustainable plan, Liechty says.
"Parents can encourage healthy eating and exercise habits from the start by leading by example, but if teens want to lose weight, parents should take them to the doctor or health-care professional and discuss how much they should lose, at what pace, and how to do it safely in a careful, planned way," she said.
If teens don't need to lose weight, they should avoid fad diets, ignore quick weight-loss promises, and not get sucked into trying extreme methods like diet pills and purging.
"The underlying issue is our relationship with food and our bodies," Liechty said. "A distorted view of one's weight status makes one more vulnerable to using unsafe weight-loss behaviors. The key is to cultivate a positive, realistic, and appreciative relationship with your body regardless of your weight, then get support to develop eating and activity habits that balance input and output, and that you can live with for long time."