Travis Saunders has put a lot of thought into it:
“…there are 4 factors that we can say (or at least I say) have contributed to the childhood obesity epidemic with relative certainty. These are:
- Sugar sweetened beverages (e.g. pop)
- Sedentary behaviour (especially screentime)
- Lack of sleep
- Adult obesity
People might be surprised that diet and physical activity aren’t on that list. But really, it comes down to measurement issues. It is certainly plausible that diet and physical activity contribute to increased childhood obesity rates. The problem is that the historical data for both of these variables is really weak, and often contradictory. The data for sugar sweetened beverages and screen time isn’t of much better quality, but the findings for both of those outcomes is much more consistent than for physical activity or diet more generally.
Note the absence of environmental pollutants.
…according to an article at MedPageToday. Here’s how the study was done:
DeBoer and colleagues evaluated the effect of sugary drinks on BMI in 9,600 children evaluated at ages 9 months, 2 years, 4 years, and 5 years, who were enrolled in the Early Childhood Longitudinal Survey — Birth Cohort, a representative survey of the U.S. population of children born in 2001.
Parents answered survey questions about beverage intake at ages 2, 4, and 5. Sugar-sweetened beverages were defined as soda, sports drinks, and fruit drinks that were not 100% fruit juice. They also looked at when the drinks were consumed — such as at meals or with snacks — and if the child was a regular or infrequent/nondrinker.
Toddlers drinking at least one sugary drink daily were much more likely to have mothers who were overweight or obese. The sugared-up kids also watched more TV and drank less milk.
No doubt you have noticed the expanding girths of U.S. yoots. What are the health implications? Research published in the New England Journal of Medicine suggests a disturbing answer.
Heavy youths tend to stay heavy as they age. Researchers looked at the incidence of overweight adolescents in the year 2000 and then estimated the prevalence of obesity in the year 2020. Thirty to 44% of 35-year-olds in 2020 are expected to be obese.
Using computer simulation, investigators estimated that by 2035 the prevalence of coronary heart disease will increase by 5 to 16% because of the increased obesity. In other words, the increasing obesity in these young and middle-aged adults will result in over 100,000 excess cases of coronary heart disease.
That is, if current trends continue. But I see nothing on the horizon likely to alter that societal trend in the near future. I’m doing my part. How about you?
Steve Parker, M.D.
References: Bibbins-Domingo, K, et al. Adolescent Overweight and Future Adult Coronary Heart Disease. New England Journal of Medicine, 357 (2007): 2,371-2,379.