Writing in the February 2006 issue of the International Journal of Epidemiology, University of Colorado law professor Paul Campos says that the "current rhetoric about an obesity-driven health crisis is being driven more by cultural and political factors than by any threat increasing body weight may pose to public health."
UNC-Chapel Hill nutrition researchers Drs. June Stevens and Barry Popkin think that while he makes a few reasonable points, mainly he is just plain wrong.
Campos and colleagues present and discuss four "claims" that they consider untrue. Those claims are that:
- Almost all countries are experiencing an obesity epidemic.
- Mortality rates increase with increasing degrees of overweight as measured by body mass index.
- The data linking overweight and obesity to adverse health outcomes are well established and incontrovertible.
- Significant long-term weight loss is a practical goal and will improve health.
"What if higher than average weight turns out to have neither much medical nor moral significance?
"The answers to these questions, all of which we believe are strongly suggested by the epidemiological literature, go far beyond the issues of body mass and health," he said. "The current scientific evidence should prompt health professionals and policy-makers to consider whether it makes sense to treat body weight as a barometer of public health. It should also make us pause to consider how propagating the idea of an 'obesity epidemic' furthers the political and economic interests of certain groups, while doing immense damage to those whom it blames and stigmatizes."
Stevens and Popkin, both nutrition professors at UNC-Chapel Hill, beg to differ.
"There is very strong evidence to indicate that...the incidence of obesity is increasing in just about all of the countries in which we have information," Stevens wrote. "... Definitions of 'epidemic' are not confined to infectious diseases but rather rest on a health phenomenon 'clearly in excess of normal expectancy.'"
She and most other health professionals see the upward shift in weight of most people of between about 6.5 pounds and 11 pounds as significant and say that it would be healthier if populations as a whole moved in the direction of preventing weight gain.
"Results differ depending on the population studied and the methods used, but the vast majority of studies show...an association between body mass index and mortality," Stevens said. "...Many studies in experimental animals have shown that those kept slender live longer than heavier animals. Recently, a study...examined the question of weight loss and mortality in an animal model. They showed that rats that were kept lean throughout their lives had the lowest mortality, and rats maintained at an obese weight had highest mortality."
Animals that were obese and then made to lose weight had mortality comparable to the consistently lean rats, she said. Mortality among rats that lost weight was slightly higher but significantly lower than the consistently obese animals.
While no one would say that significant weight loss is an easy goal, that does not make it impractical, Stevens wrote. "...There is ample evidence to support that adoption of a lifestyle that reduces excess weight by means of a healthy diet and increased physical activity will improve health."
Two keys points to keep in mind, she said, were that the global population is getting heavier and that being obese causes serious health consequences.
"...Obesity remains an exceptionally important preventable cause of disease and death," Stevens wrote. "Finally, after many years of inattention the scientific community has turned its considerable resources to obesity. The vast majority of researchers and practitioners champion this move, not because it will increase their personal fortune but because it offers the opportunity to make important improvements in human health."
Popkin and Dr. Soowon Kim, a fellow in the University of California at San Francisco's family and community medicine department, conducted a wide-ranging review of the scientific literature. They wrote that any such review "produces overwhelming evidence of the global obesity pandemic and the strong adverse consequences of obesity."
Among the health consequences they cite as arising at least in part from overweight and obesity are hypertension, cholesterol problems, insulin resistance, cancers of the colon, breast, esophagus, endometrium and kidney, type 2 diabetes, coronary heart disease, stroke, gallbladder disease, osteoarthritis and psychological issues.
"Overweight persons ... also retire earlier, go at younger ages into nursing homes, have higher absenteeism rates and are more likely to be disabled," Kim and Popkin wrote. "...It is often the poor, people with lower socioeconomic status and some socially disadvantaged racial/ethnic groups that disproportionately suffer from the obesity epidemic, both adults and children alike," the two wrote. "When the alarming increase in weight nationally and globally is ignored, these already marginalized and stigmatized subgroups, socially and health-wise, will suffer even greater from obesity-related morbidity and mortality.
"We feel that treating a real health problem as non-existing is equally irresponsible as blaming the victims only."
The UNC-Chapel Hill nutrition department is jointly housed in the schools of public health and medicine.
Note: Stevens can be reached at (919) 966-1065 or firstname.lastname@example.org; Popkin at (919) 966-1732 and email@example.com.
School of Public Health contact: Ramona DuBose, (919) 966-7467
News Services contact: Deb Saine, (919) 962-8415