Junkfood Science: JFS Special Report: Major findings on childhood obesity programs

April 11, 2008

JFS Special Report: Major findings on childhood obesity programs

This week, we learned how effective the School Nutrition Policy Initiative has been in reducing childhood obesity. This comprehensive initiative includes all of the school-based programs, in accordance with the U.S. Centers for Disease Control and Prevention’s “Guidelines to Promote Lifelong Healthy Eating and Physical Activity,” that are being proposed across the country. The long-awaited results of this intensive 2-year study were just published in the journal Pediatrics.

This is a critically important news story because there is a lot riding on proving these childhood obesity initiatives are effective — for literally thousands of organizations, special interest groups and government agencies across the country working to prevent childhood obesity and promote their ‘healthy’ eating and physical activity programs, as well as billions of dollars in government money at stake. [The CDC’s budget for its healthy eating and physical activities, alone, has grown 2,000% since 1999.] And, most at stake is the welfare of our children.

Since every school-based childhood obesity intervention to date has failed to show lasting improvements in children’s diets, activity levels or health outcomes, or in reducing obesity, this study has added importance. As the U.S. Preventive Services Task Force and even the Institutes of Medicine have concluded after reviewing 6,900 studies and abstracts, there is no quality evidence to support these childhood obesity interventions. And the government’s own statistics even negate the need for them, as there have been no significant increases in the numbers of children considered “overweight” since 1999-2000 and children are healthier and expected to live longer than at any other time in our history.

The results of this study should have been big news.

Yet, only a small handful of news outlets even covered the story. From the press release, they reported that a new study had shown that “small changes in schools lead to big results.” We were told that these school-based interventions “reduced the incidence of overweight by 50%,” and offer a way to prevent childhood obesity on a large scale. Given the major importance of this study, where was the media fanfare? Perhaps, it is hoped that we won’t look too closely at what the study actually found...

What is SNPI and the Healthy School Toolkit?

The School Nutrition Policy Initiative (SNPI) was created by The Food Trust in Philadelphia, one of Robert Wood Johnson Foundation’s key “obesity fighting grantees,” according to Dr. Risa Lavizzo-Mourey, M.D., RWJF president, in her 2006 address. The Food Trust’s efforts have resulted in the strictest school nutrition policies in the country, she said. Its policy and environmental strategies were also highlighted in RWJF’s Childhood Obesity Framing Document (2006) as working to build the evidence for halting childhood obesity by improving healthy eating and increasing physical activity among kids.

According to The Food Trust, this comprehensive initiative was developed to provide young people with “the skills, social support and environmental reinforcement needed to adopt long-term healthy eating habits.” The Food Trust’s Task Force began piloting the policy in Philadelphia schools in 2001. With CDC grant funding, it was expanded into a two-year CDC study that began in October 2002 in partnership with Temple University’s Center for Obesity Research and Education (CORE; previously with the University of Pennsylvania’s Weight and Eating Disorders Program). The lead investigator of this study (ClinicalTrials.gov ID NCT00142012) was Gary D. Foster, Ph.D. at the University.

The Food Trust’s website is already promoting the SNPI as having been proven to reduce the incidence of childhood overweight by 50%, based on the results of this new study, and has produced a Healthy School Toolkit based on its program that is being distributing to schools, parents and administrators across the country.

The study was conducted in ten Philadelphia inner-city schools that had over 50% of the students eligible for free or reduced-cost meals (household income <185% of the poverty level adjusted for household size), and predominately minority pupils. A total of 1,349 students (average age 11) were enrolled in the study — 749 in the five intervention schools and 600 kids in the control schools.

Inner-city schools were used because, according to The Food Trust, that’s where there is the greatest obesogenic environments, with fewer opportunities to go outside and play, inferior grocery stores so people eat fewer fruits and vegetables, and poorer families. “When money is tight, it’s cheaper to feed your kids convenience foods, which are usually higher in fat and calories,” professor Foster said in the press release. “Multiple environmental factors are responsible for the childhood obesity epidemic.”

According to professor Foster and colleagues with The Food Trust, the SNPI’s key components are: “school self-assessment; nutrition education; nutrition policy; social marketing; and parent outreach:”

Education focused on healthy eating. All school staff in the intervention schools were offered about ten hours per year of training on healthy eating education, as well as “nutrition and physical activity theme packets” to integrate into classroom lessons, cafeteria promotions, and parent outreach. Each student was given 50 hours of healthy eating education per school year, based on the CDC “Guidelines for School Health Programs to Promote Lifelong Healthy Eating.” The obesity epidemic claims in this document have been covered at length at JFS, as have its claims that unhealthy eating is responsible for obesity, heart disease, cancer and diabetes. We’ve also examined the controversy over the science and the evidence for potential harm in its “healthy eating” recommendations for kids of low-fat, low-sugar, low-salt diets; and the focus on fruits and vegetables as meaning healthy eating. According to the oft-repeated CDC claims in these guidelines, most children don’t eat enough fruits and vegetables, with the average young person said to be eating only 3.6 servings of fruits and vegetables and 42-42% not eating any at all. According to the study authors, the purpose of this nutrition education “was to show how food choices and physical activity are tied to personal behavior, individual health, and the environment.”

In addition, healthy eating was integrated into every classroom subject, such as using food labels to learn fractions and nutrition as food writing assignments, the authors said.

Food policies. All foods sold and served in the intervention schools were changed to meet tight guidelines, which included beverages that could only be water, low-fat milk (8oz) or 100% juice (6oz); snacks that had to be less than 7 grams of total fat, 2 grams of saturated fat, 360 mg sodium and 15 grams of sugar per serving; and all soda and vending machines and ala carte food items were eliminated.

Social marketing strategies. Several techniques were used to apply social pressure to encourage kids to eat healthy snacks and beverages, whether purchased or brought from home, according to the study authors. The message “Want Strength? Eat Healthy Foods” was posted to provide frequent exposure. They rewarded kids for healthy eating behaviors, not just with prizes but through social privileges that ostracized children who were eating ‘unhealthy.’ These may be some of the most troubling aspects of the program. [Click on image to enlarge.]

Parent involvement. Teachers targeted family members by meeting them in their homes and school association meetings, report card nights, parent education meetings, and weekly nutrition workshops. The home program parents were to institute at home was the “2-1-5 challenge to be less sedentary (<2 hours per day of television and video games), to be more physically active (>1 hour per day), and to eat more fruits and vegetables (>5 per day).”

“Healthy eating” completely absorbed the school environment. As the director of nutrition education at The Food Trust said in the press release: “We incorporated healthy eating into every part of the school day in order to have a greater impact on the students. The intervention fundamentally changed the school environment.”

Monitoring and reporting

The children were weighed and measured at the beginning of the study (spring semester) and at 1 and 2 years by a trained member of the research team. The study was not blinded, so the research team knew which children were in the intervention school and which were in the control group. The children’s diets were assessed using a 152-item food frequency questionnaire completed by the children. Physical activity was similarly self-reported, rather than using accelerometers.

About 62.6% of children completed the 2-year study. To account for attrition, the researchers imputed missing data using an algorithm (Markov chain Monte Carlo) that filled in the blanks with “plausible values”

While it might appear the SNPI program was about “healthy eating and physical activity,” the primary and secondary outcome measures were only about weight loss and percentiles in the overweight categories.

As we know, data can be reported in a myriad of ways. These researchers used the new BMI-based growth charts, rather than the traditional growth charts based on children’s heights and weights. They did not provide actual weights and heights, either, which makes the information much harder for the public to get a clearer picture of what really happened.

Traditionally in the U.S., based on data on American children, weights above the 95th percentile have arbitrarily been labeled “overweight” and weights in the 85th-95th percentile termed “at risk for overweight.” As we know, children grow in diverse patterns and spurts, and all kids are at different stages of maturity at various ages. It’s not uncommon for some to plump up before shooting up. Children in the upper percentiles are not “sick” just because they are larger, so doctors have traditionally resisted labeling children as “overweight.” The new cut-off lines for the 85th and 95th percentiles of BMI issued in 2000 with new growth charts, however, instantly placed nearly two-thirds of kids at higher percentiles and more children were likely to be classified as above the 85th percentile, according to scientists at the CDC’s National Center for Health Statistics. Compounding perceptions of a growing epidemic of “obese” children and to medicalize overweight, an increasingly popular tactic among obesity interests is to relabel the children in the 95th percentile as “obese” and those at 85th percentile as “overweight.” [More information on the controversies about BMIs in children and the health implications are here.]

By reporting just the total percentages of kids crossing arbitrary classification cut-offs, rather than actual changes in weights, heights and BMIs, we can be left with inaccurate perceptions. So, we’ll examine the data both ways and see for ourselves.


The only finding reported in the news was that the incidence of “overweight” was 50% lower in the intervention group compared to the control group. This was relative risk, rather than actual numbers. It does not mean that the number of overweight children were halved.

What wasn’t reported is that this reflected a difference of only 11 kids (an actual 7.44% difference between the groups) who had newly crossed that arbitrary threshold at the 2-year weigh-in.

The new cases classified as “obese” differed by only 3 children (0.61% actual difference) between the groups. Next year, a significant number of those new cases of obesity and overweight will have fallen below the line and won’t be included in that category anymore. In fact, the percentage of kids who had dropped out of the categories from the year before provide an example of that phenomenon — among the intervention pupils, 10.68% of the children had fallen out of the “overweight” category as they grew and another 10.94% had fallen out of the “obese” category.

Since we know that kids fluctuate as they grow, with some falling on one side of a line one year and on the other side the next, the overall prevalence of obesity provides a clearer picture of the impact the interventions had over the years. Did the interventions actually reduce the total numbers or percentages of students who were obese compared to the students in the control group?

The percentage of children in the 95th percentile (classified as “obese”) increased in the intervention group by 1.25% and in the control group by 1.37% — a nonstatistically significant effect (a theoretical actual difference of 0.13%). But, remember the percentages of children in all the categories are fluctuating. What were the effects of the interventions on the overall numbers of children considered “fat?” The researchers reported:

After 2 years, there were no differences between intervention and control schools in the prevalence of obesity. After collapsing the overweight and obese weight categories [all those above the 85th percentile], there was no statistically significant difference between the intervention and control schools in the prevalence of overweight or obesity. (P<0.07)

They concluded that, except for that one happenstance finding on the incidence of “overweight”:

The intervention had no effect at the upper end of the BMI distribution, that is, on the incidence, prevalence, or remission of obesity.

Even more telling, they found:

There were no differences between groups with respect to changes in BMI (P <0.71) or BMI z score. (P <0.80).

In other words, the program had no effect on the children’s actual measurements of height and weights. To bring home just how ineffective this massive intervention was, looking at the weight and height growth curves, it is clear that the pre-pubescent years, especially for girls (whose natural fat and weight gain are most often mislabeled as "overweight"), are a period of especially pronounced growth spurts. Given the girls' average percentiles on the BMI growth curves, for example, they would have grown more than 4 inches in height and gained about 25 pounds during the study years. Yet, incredibly, their average BMI changes ended up within one-tenth of a BMI unit different between the intervention and control group — not even a pound — and not tenable given how they were measured.

Clearly, the School Nutrition Policy Initiative failed to reduce overweight or obesity in the children.

Did it do any good?

You might be tempted to think that after 2 years, this pervasive school-based “healthy eating” initiative might have at least led the kids to eat more fruits and vegetables. Before the study began, these inner city, poor and minority children had been eating an average of 5.64 servings of fruits and vegetables a day.

Remember, the stereotype about how awful poor, minority children in obesogenic environments must be eating?

Among the kids who completed the study, the number of servings of fruits and vegetables they were eating — after 2 years of “healthy eating” education — had dropped. The intervention group had decreased their servings to 4.17 a day. The control group kids were actually eating slightly more fruits and vegetables than the kids in the intervention group.

Most worrisome, how many young people had eliminated meat, milk, fats and carbs from their diets believing they were eating “healthier” and that those foods made them feel weak and unhealthy? How many were restricting their eating trying to control their weights or due to fears of ‘unhealthy’ foods that would give them heart disease, cancer and diabetes? How many were already developing dysfunctional relationships with food that will follow them for years to come, rather than eating normally? While the authors reported no nutritional analyses, and the dietary intakes were self-reported, the available data indicates cause for concern. The kids in the program were eating about 234 kcal/day less on average than the control group (notice, once again, with no effect on weights). Based on their average heights, weights, age, and activity levels, it would appear these girls were undereating — and eating fewer calories than recommended by the Baylor College of Medicine Energy Needs Calculator for children (used by the 2005 U.S. Dietary Guidelines) for good health, growth and development, and nutrition.

There is also no evidence to support that these interventions improve the health of these children, which should be a greater priority than what size clothes they wear. And what happened to their academic performance and test scores, while they were spending so much class time counting calories and reading food labels? Given the CDC, RWJF, and thousands of special interests are promoting these comprehensive school “healthy eating and activity” programs which have no evidence of effectiveness, parents and taxpayers might ask if educational and healthcare resources might be better spent in other ways that could better children’s futures, especially for underprivileged families.

© 2008 Sandy Szwarc

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