Everybody seems to be in agreement that childhood obesity has become a huge health problem. Here in the United States, about 17 percent (12.5 million) of our children and teenagers are obese, a rate that's tripled since 1980.

What people seem to disagree about, however, is what to do about it. Earlier this month, the Georgia Children's Health Alliance launched a controversial anti-obesity ad campaign that uses brutally frank photos and videos of overweight kids. The photo cutlines say things like, "Warning: It's hard to be a little girl if you're not," while the videos show obese kids making painful statements about their weight. In one, "Bobby" solemnly asks his (also obese) mother, "Why am I fat?"

stopchildhoodobesity.com

Anti-obesity campaigns like the one designed by the Georgia Children's Health Alliance may be counter-productive.

Nor is the United States the only country struggling with this issue — or coming up with increasingly desperate-sounding strategies for fixing it. Even in France, where the child obesity rate is under 10 percent, health officials have become alarmed because the rate has climbed rapidly in recent years. This month, one of France's leading diet gurus, Dr. Pierre Dukan, suggested that his country's high-school students be awarded extra academic credit if they maintain a healthy (non-overweight) body mass index (BMI) of 18 to 25.

Study: Teen dieting doesn't work
I could almost hear Dianne Neumark-Sztainer cringe over the phone line when I told her of Dukan's proposal. "I don't think that's a good idea," she said. Neumark-Sztainer, a professor of epidemiology and community health at the University of Minnesota, is an expert in adolescent health and nutrition as well as in obesity and eating disorders.

sph.umn.edu

Dianne Neumark-Sztainer

Last week, she and her colleagues published a new study from the U of M's Project EAT, an ongoing research project that began surveying Minnesota teens about their dietary and physical activity habits in the late 1990s. This latest study, which included data from 1,900 middle-school and high-school students, found that teens who persistently turned to dieting and unhealthy weight-control behaviors — things like skipping meals, taking diet pills and fasting — were more likely to gain weight as they moved into young adulthood than teens who didn't diet.

Specifically, young women who persistently dieted (who said they were dieting at two separate time points during the study) were found to have increased their BMI by an average of 4.6 units after 10 years, while the study's non-dieting young women gained an average of only 2.3 units. Young men who persistently dieted during the study period increased their BMI by an average of 7.0 units compared to a 3.5 BMI unit-increase among their non-dieting male peers.

Those are significant differences, said Neumark-Sztainer. "And the fact that it was over a 10-year period is really quite alarming," she added.

It didn't matter if the teens were or were not overweight at the point they began filling out Project EAT's surveys. For example, overweight adolescent girls in the study who used unhealthy weight control behaviors increased their BMI by an average of 5.19 units during the study while overweight adolescent girls who refrained from those behaviors gained an average of only .15 BMI.

The study, which appears online in the Journal of Adolescent Health, also found that the teens who started but then stopped dieting gained less weight than those who kept at it.

"Our findings do not lend support to the idea that dieting is a proxy for a tendency to overeat and that if one stops trying to diet, one will overeat and gain weight," Neumark-Sztainer and her co-authors wrote.

There is also some encouraging news from recent Project EAT data. In a second study, which appears in the January issue of the journal Preventive Medicine (but was published online last fall), Neumark-Sztainer and her colleagues found that fewer teenage girls are dieting and engaging in unhealthy weight control behavior than a decade ago. Specifically, the researchers compared the surveys filled out by 3,000 teenage girls in 1999 with a similar number of surveys completed in 2010. They found that dieting had decreased by 6.7 percent and unhealthy weight control behavior by 8.2 percent. One extreme and particularly disturbing behavior — self-induced vomiting — had fallen by 4.5 percent.

This data had troubling news as well. The prevalence of obesity among teenage boys was found to have increased by 7.8 percent from 1999 to 2010. The numbers were particularly disheartening for boys from minority populations. The prevalence of obesity among African-American boys rose from 14.4 percent to 21.5 percent and among Hispanic boys from 19.7 percent to 33.6 percent.

A search for solutions
If traditional dieting fails to help young people achieve and maintain a healthy weight, then what will help them?

One possibility, said Neumark-Sztainer, is to shift the focus toward helping young people avoid overeating rather than asking them to under-eat. This strategy requires such tactics as counseling overweight teens to identify their emotional reasons for overeating and teaching them about appropriate portion sizes and healthier food options.

"The natural reaction of a parent of an overweight child is to encourage them to go on a diet," said Neumark-Sztainer. "But we really need to educate parents and adolescents directly that this is not the right way to go."

Punishing young people for being overweight, as Pierre Dunkin's proposal would do, also doesn't work, she stressed. A better idea, she said, would be to make sure children and teenagers engage in physical activity each day and that fresh fruit and other healthful foods are widely available, including at school, for meals and snacks.

And although Neumark-Sztainer believes the individuals behind the Georgia ad campaign are well intentioned, she said it's unlikely that their posters and videos will be effective in helping young people lose weight. That's because the ads may add to the negative stigmatization of overweight kids.

"You may need to recognize that you have a health problem and that you need to lose a few pounds, but that's very different than feeling just horrible about yourself," she said. "Our research shows that when teenagers feel worse about their body, they are more likely to gain weight over time."