Thursday, August 25, 2011

"Fat Children Eat Less Than Their Thinner Peers"!?



"Fat Children Eat Less Than Their Thinner Peers". That's the tweet Linda Bacon from HAES fame sent out to her followers at 9:55am yesterday morning.

It certainly fits the HAES narrative that the world's completely backwards in regard to anything and everything weight related.

Sadly it also continues Linda's confusing practice of tweeting bad data.

Linda's HAES platform, whether you agree or disagree with it, rests on the shoulders of her critical analysis of the medical literature on obesity, and her take is that many of the studies with which researchers and clinicians have vilified obesity, were either poorly designed or poorly analyzed.

But yet here's Linda promoting a Medscape news piece on a non-peer reviewed, poster presentation from a pediatric conference, where the findings are readily debatable.

The poster whose findings she was authoritatively retweeting, tracked the dietary recall of 12,316 children between the ages of 1 and 17 years of age.

Tweet and actual data accuracy aside, what the researchers truly reported wasn't that all fat children eat less than their thinner peers, but rather that the caloric intake of overweight and obese kids aged 1-7 exceeded that of their thinner peers but that the pattern "flipped" at age 7.

So what does "flipped" mean?

According to the poster, 9-11 year old kids with overweight and obesity reported consuming 1,988 calories daily, while their thinner peers reported consuming 2,069 (a difference of 4% which I'd venture isn't likely to be a statistically significant one). The study's 15-17 year olds with overweight and obesity reported consuming 2,271 calories daily, while their thinner counterparts reported 2,537 (a difference of 12%).

But can we really trust the dietary recall of children with overweight and obesity?

I'm not trying to be harsh. This world is not kind to overweight and obese children (or adults), and Linda would certainly know better than most of the stigma, bias and bullying those kids likely face on a daily basis - potentially even from their parents, their schools and their physicians. I don't think it would be an even remotely surprising finding that when participating in dietary recall surveys, children with overweight and obesity, especially older children who've had more time to experience hateful weight bias, might be more likely to under report.

So is there data to suggest that's a real possibility? Could these kids be under-reporting by more than the 12% seen in the oldest age group?

Absolutely.

In fact just this past February there was a review paper published in the International Journal of Pediatric Obesity titled, Assessing dietary intake in children and adolescents: Considerations and recommendations for obesity research. Regarding under-estimation, here's what the review paper's authors had to say,

"One of the most robust findings in dietary studies of children and adolescents is the positive association between under reporting and increased body fatness, particularly in adolescents (4,14,15). This is consistent with studies in overweight and obese adults (16). The extent of mis-reporting irrespective of weight status increases with age and has been reported as 14% of energy intake in 6-year-olds (17), 25% in 10-year-olds (18) and 40% (4,19) to 50% (14) in obese adolescents.."
The authors further report that the type of study most likely to suffer from under-reporting is the very type performed for the poster in question,
"Studies characterising under-reporting have focused on total diet assessment methods and in particular, energy intake"
To be clear, I think Linda Bacon's contribution to the field of overweight and obesity research, as well as public policy and attitude, is tremendously important. I just can't rationalize the scientifically critical Linda Bacon with her Twitter persona that seems to just retweet anything that satisfies the HAES narrative, no matter how weak or poorly designed the study (or in this case, the poster) may be.

Sigh.

There's got to be a better way to fight misinformation and statistically indefensible conclusions than the promulgation of misinformation and statistically indefensible conclusions.

Magarey, A., Watson, J., Golley, R., Burrows, T., Sutherland, R., McNaughton, S., Denney-Wilson, E., Campbell, K., & Collins, C. (2011). Assessing dietary intake in children and adolescents: Considerations and recommendations for obesity research International Journal of Pediatric Obesity, 6 (1), 2-11 DOI: 10.3109/17477161003728469

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