Junkfood Science: Look before we LEAP again

September 07, 2009

Look before we LEAP again

Clinical guidelines are used to measure the quality of care provided by physicians and are purportedly evidence-based. National childhood overweight and obesity policies in the United States, United Kingdom and Australia call for primary care physicians and pediatricians to monitor children’s BMIs and to counsel youngsters with BMIs ≥85th percentile and their families on diet, physical activity, sedentary behaviors and adopting healthy lifestyles.

“Evidence supporting such an approach in primary care, however, is conspicuously lacking,” said pediatrician Dr. Melissa Wade M.D., associate director of the Centre for Community Child Health at the Royal Children’s Hospital and the Murdoch Children’s Research Institute in Melbourne, Australia, and colleagues.

To determine the effectiveness of screening and counseling for child overweight and obesity, a second Live, Eat and Play (LEAP) randomized controlled trial was launched. The long-awaited results were just published in the British Medical Journal.

As readers will remember, the first LEAP trial had been conducted at 29 Melbourne medical clinics and involved 3 months of interventions by primary care physicians to teach overweight children and their families healthy lifestyle changes, with 12 months of follow-up. The doctor-based weight management program failed to make any sustained changes in the larger children’s BMIs, failed to change obesity rates, and failed to make any difference in the children’s health status compared to the control group. Thinking a larger study, more training for the doctors and more intense interventions might be able to demonstrate a benefit, LEAP 2 was begun. This larger study began in May 2005 and was due to be completed in September 2007.

Overview of LEAP 2

This trial (registered ISRCTN 52511065), included 45 family practices and 66 general practitioners in Melbourne. From May 2005 through July 2006, nearly 4,000 children, aged 5 to 10 (average 7.5 years old), were screened and 258 who were overweight or obese, according to the International Obesity Taskforce definitions, were enrolled into the study. They were independently randomized, with 139 in the intervention group and 119 in the control group, and were well matched by every measure evaluated. The study investigators remained blinded to who was participating in the study, and the physicians were blinded to the children among their large patient base in the control group. The physicians received training on weight management counseling, which included five hours of instructions, role modeling scenarios and two simulated counseling session, and only those with high scores were allowed to participate.

The children and their families received targeted information on healthy behavioral changes (reducing sedentary time, increasing physical activity, increasing water consumption, improving family eating habits and making low-fat food selections) and agreed to change contracts. For three months, the parents were offered four physician consultations which reinforced family-focused healthy weight, diet and lifestyles changes, with an average of one counseling per month attended.

The family’s socioeconomic status was quantified using the Australian census based Index of Relative Socio-economic Disadvantage score, and the parents BMIs were followed. The parents completed 4-day food diaries on the children, and completed questionnaires on their physical activity and weight concerns. The children’s health status was followed by their pediatricians and graded on 23 quality measures; their weights, heights, waists and activity levels (measured by accelerometry) were followed at six and 12 months; and the children completed questionnaires to evaluate their body dissatisfaction, perceived physical appearance and self worth.


There was no statistical difference between the intervention and control groups after 6 months or after 12 months in the:

● children’s BMI

● children’s waist circumference

● either parents’ BMIs

● children’s physical activity (counts/minute on accelerometry) or percentage of time spent moderately to vigorously active or percentage of time spent in low activity

● children’s diets

● children’s physical or psychosocial health scores

● children’s degree of body dissatisfaction

● children’s positive/negative feelings about their appearance or self worth

There was no statistical difference in outcomes among children whose parents attended all the consultations and those who attended fewer. There was no statistical differences based on socioeconomic status. Healthcare costs were significantly higher in the intervention group, based on the costs of adhering to the intervention guidelines.

The sample size and consistent follow-up with their doctors for a full year, and the extremely high retention rates (92.8% and 96.6%), enabled the researchers to conclude that there was no clinically meaningful benefit from the diet and activity interventions — as called for in clinical guidelines and public health policies — on the children’s BMI trajectory, physical activity or nutrition.

These findings are at odds with national childhood overweight and obesity policies, including in Australia, UK and the US, the authors concluded. All childhood overweight and obesity policies and guidelines are similar (work to improve diets and increase physical activity) and have similarly been shown to be ineffective. Despite high political appeal, they said, recent systematic reviews of the evidence have been unable to support screening children for overweight or obesity because of the lack of weight management strategies that have demonstrated efficacy and the lack of evidence that benefits outweigh the harms. The authors were unable to find a clinical trial of primary care interventions and screening for child overweight and obesity that had been shown to be effective, as the few trials had all proven to be ineffective in reducing BMI compared to controls.

These findings concur with every other comprehensive intervention trial, including school, state and community based, as well as the findings of the U.S. Preventive Service Task Force, which reviewed nearly 40 years of evidence on screening and interventions for childhood and adolescent overweight — some 6,900 studies and abstracts. The USPSTF had concluded that there is no quality evidence to support that overweight or obesity in youth is related to health outcomes or predicts fitness, blood pressure, body composition or health risks. The USPSTF found insufficient evidence to recommend routine screening for overweight in children and adolescents as a means to improve health outcomes. It did, however, note potential harms of screening programs. According to the USPSTF Childhood Obesity Working Group, no scientific review has been able to find quality evidence that any program to reduce or prevent childhood obesity — no matter how well-intentioned, comprehensive, restrictive, intensive, long in duration, and tackling diet and activity in every possible way — has been effective, especially in any beneficial, sustained way. Nor has any program been able to demonstrate improved health outcomes or physiological measures, such as blood lipids (“cholesterol”), glucose tolerance, blood pressure or physical fitness. Nor has any diet or exercise intervention in children been shown to lead to better health outcomes in adulthood. Not only did the USPSTF find no evidence to support the effectiveness of counseling for healthy eating in young people, it also found no evidence to support low-fat diets in children and, instead, found growing evidence for harm. Politically popular childhood obesity interventions don’t work, of course, because they’re based on false premises about the causes of children’s sizes.

How many more years and how many more times does the evidence have to continue to show the same thing before the public and medical professionals say “enough” and demand evidence-based public health policies and clinical guidelines for our children?

How long before taxpayers begin to hold politicians and stakeholders accountable for the massive amounts of public moneys and resources spent in the name of a childhood obesity epidemic that could have gone towards improving educational opportunities and healthcare for children and families?

© 2009 Sandy Szwarc

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