The Myth of an “Obesity Tsunami”

Everyone knows The Truth about obesity: we’re getting fatter each year. Our growing girth is termed everything from the “pandemic of the twenty-first century” to an “obesity tsunami”. But the evidence is now flooding in from both America and England that obesity is the epidemic that never was.

Two studies produced by the US Centers for Disease Control and Prevention (CDC) and published last week in the Journal of the American Medical Association – one about obesity in children and adolescents, and the other about adult obesity – completely undermine the claims of an obesity epidemic.

Both studies are based on information from the National Health and Nutrition Examination Survey from 2007-08, which is a representative sample of the American population. The survey measured the heights and weights of 3,281 children and adolescents and 219 infants and toddlers, as well as 5,555 adult women and men. The study of children and adolescents looked at the body mass index (BMI) of children and adolescents over five time periods between 1999 and 2008, the decade during which child obesity was widely described as America’s preeminent public health problem.

[E]vidence is now flooding in from both America and England that obesity is the epidemic that never was.

The results are striking. During none of the five periods was there a statistically significant trend, except for boys at the highest BMI levels. In other words, if there was a spike in obesity, it was confined to a very small number of very obese boys.

What about the adult “couch potato” generation? Here, again, the results put the lie to claims of an obesity tsunami. In the study of adults, the researchers also looked at obesity trends over the past decade. For women, there were no statistically significant changes in obesity prevalence over the entire decade, while for men there were no prevalence differences during the last five years of the decade. As the researchers note, obesity prevalence may have “entered another period of relative stability”.

A similar absence of an obesity epidemic is to be found in England. According to the Health Survey for England, which collected data from 7,500 children and almost 7,000 adults, there has been a decline in the prevalence of overweight and obesity for adult men, while for adult women prevalence has remained the same.

Comparing the results of the survey for 2007 with those of 2004, there have been either declines or no significant changes in male prevalence of overweight and obesity in all age groups from 16-54. As for children, the survey finds: “There was no significant change in mean BMI overweight/obesity prevalence between 2006 and 2007, and there are indications that the trend in obesity prevalence may have begun to flatten out over the last two to three years.”

For example, there was a decrease in obesity in girls aged two to 15 years old between 2005 and 2006, from 18 per cent in 2005 to 15 per cent in 2006. Among boys aged two to 10 years old, the prevalence of overweight declined from 16 per cent in 2005 to 12 per cent in 2006. According to the results, overweight and obesity have been declining amongst boys and girls aged two to 15 since 2004. In girls, obesity prevalence levels are largely unchanged from where they were in 2001.

The findings of the English survey not only contradict the claim that we are in the midst of an obesity epidemic, but they also debunk the public health establishment’s erroneous claim that increases in children’s weight are due to junkfood advertising and too many sugary soda drinks. According to the survey, the root cause of any weight gains that one does see appear to lie in physical activity levels. For example, “21 per cent of girls aged two to 15 in the low physical-activity group were classed as obese compared with 15 per cent of the high group”.

A similar pattern was found in the 2006 survey, which found that 33 per cent of girls aged two to 15 with low levels of physical activity were either overweight or obese compared with 27 per cent of those with high levels of physical activity. As with smoking, obesity prevalence was higher in both boys and girls in the lowest income group.

Clearly, governments’ current course of draconian regulatory treatment seeks to cure an illusory disease. The nanny state’s infatuation with an obesity epidemic that does not exist is a searing indictment of this particular public health crusade.

Patrick Basham directs the Democracy Institute and is a Cato Institute adjunct scholar. John Luik is a Democracy Institute senior fellow. They are co-authors, with Gio Gori, of Diet Nation: Exposing the Obesity Crusade.