Junkfood Science: Can anyone be taking this seriously anymore?

November 07, 2008

Can anyone be taking this seriously anymore?

The more the evidence keeps failing to support an obesity-related international health crisis, the more hysterical and frantic the claims become. This week, our friends in the UK have been threatened with proclamations that obesity is the new Black Death and will kill as many of their children and that the obesity crisis will cause cancer deaths to double in the UK by 2050. There can be no other response to predictions with no science behind them than to look to British comedian Dr. Graham Chapman (1941-1989), who would appear in the middle of a skit as the Colonel and pronounce:

“You’ll have to stop this now. It’s getting altogether too silly.”

Imagine the zany sketches that the Monty Python might do today. Yes, Dr. Chapman was a practicing M.D. before pursuing comedy as a member of the Monty Python troupe. He would have had a field day with this week’s news. This morning, the Western Mail in Wales reported:

Obesity is new Black Death threat

OBESITY poses as big a threat to the lives of Welsh children today as the Black Death did to others centuries ago, First Minister Rhodri Morgan said yesterday. He told a conference of health service managers that Wales must address the health consequences of the nation’s poor diets and lifestyles, which he fears could lead to children having a lower life expectancy than their parents for the first time in 700 years... “We now have new diseases caused by inappropriate diets – we have sluggish and low heart and lung functions. The rising generation of children may be the first generation, because of obesity, to have lower life expectancies than their parents for centuries – probably since the Black Death.”…

Obesity worse than bubonic plague? The Black Death of the Middle Ages was the deadliest pandemic in human history and wiped out a third to half of Europe’s population in just two years. The last time we heard a government official say obesity is deadlier than Black Death was back in April 2005, when the CDC was trying to translate their science on the obesity crisis more effectively.

There is no evidence to even suggest today’s children will have lower life expectancies than their parents for the first time since 1300 A.D.

The Health Survey for England data shows there’s been very little change in child obesity rates over the past decade. As Dr. Peter March, co-director for the Social Issues Research Centre in Oxford, UK, had concluded: “There have been no significant changes in the average weights of children over nearly a decade. This can be taken as evidence that there has been no ‘epidemic’ of weight gain.” And children today just keep getting healthier and healthier and living longer and longer. There is no evidence of a plague of obesity.

This week, the Telegraph ran a story — or, it would be more accurate to say they rewrote a story from July that had called obesity a ticking cancer time bomb [discussed here], with added panic. Quoting the World Cancer Research Fund, this week’s version said obesity will cause an explosion of cancer:

Obesity crisis 'could cause cancer cases to double by 2050'

The chance of developing major killers like breast and kidney cancer rises as people become increasingly overweight, studies have shown. Experts predict that if trends continue up to one third of British women and half of men could be obese by 2050, up from around a quarter at the moment. A leading cancer professor warns that Britons are "sleepwalking" into an explosion of cancer cases unless we stop piling on the pounds at a conference on obesity and the disease in London today. Professor Martin Wiseman, the medical and scientific adviser to the World Cancer Research Fund (WCRF) charity, says that today's children will face increasing rates of cancer as they grow up unless tough action is taken. He will say: "Unless something happens soon to stop the increase in obesity then we are sleepwalking towards a situation where Britain will be facing more cancer cases than ever before. The evidence now shows that, after not smoking, maintaining a healthy weight is the most important thing you can do for cancer prevention.”…

Research has shown that becoming overweight increases the likelihood of developing six different types of cancer, including breast, kidney, womb and pancreas… A healthy weight is defined as a BMI of between 20 and 25… Studies have shown that even within the healthy BMI range, the heaviest people are more likely to develop some types of cancer…

There’s been no new research. The research referred to in this article turned out to be the Second Expert Report issued last fall by the WCRF and fellow member of the World Cancer Research Fund global network, the American Institute for Cancer Research. The Report, called Food, Nutrition, Physical Activity and the Prevention of Cancer: a Global Perspective, was said to have found the most convincing evidence yet that being fat causes cancers and that diet and weight management can prevent cancer.

As investigated here, however, the report reviewed 2,471 epidemiological studies on 17 cancers and the data revealed no tenable correlations between cancers and foods or body fatness, nor between cancer deaths and BMIs. And, while the authors had created their own unusual methodology for defining proof and proving causation from correlations, the evidence still failed to credibly support claims that cancers are mostly preventable by following their stringent diet recommendations or by losing weight. None of the relative risks they reported were more than chance, statistical bias or the effects of confounding factors. Of the 17 cancers they reviewed, none were found to have tenable correlations with foods (sugars or sugary drinks, fats, meats, fruits, vegetables, legumes, vitamins, alcohol or processed foods) or body fatness.

The WCRF has published abbreviated versions of the report for consumers called Guidelines for Cancer Prevention and Eating Well for Cancer Prevention. Among claims that have failed to be supported in randomized clinical trials are the cancer-preventative benefits of antioxidants in fruits and vegetables, low-salt diets, and dietary fiber; and claims that red meats, processed meats (nitrates) and sugar causes obesity and increase risks for cancers.

It’s not difficult to understand why the WCRF isn’t eager to report the clinical evidence, after all, it was the first cancer charity founded on creating an awareness of a link between diet and weight to cancer.

The Telegraph article goes on to report that a consumer survey found only half of the population knows (believes?) there’s a link between obesity and cancer. Interpret that how you wish.

At the end of the article we learn this story has resurfaced as publicity for the Association for the Study of Obesity (ASO) conference held this week called Obesity and Cancer, and organized in conjunction with WCRF International. The conference is promoting this “extremely important subject because there is convincing evidence that excess body fat is a cause of several types of cancer,” said ASO chairman.

No matter how many times the scares are repeated or how alarming they sound, they can’t drown out the research available from around the world that disproves them. Within days of the WCRF report, scientists at the National Center for Health Statistics at the U.S. Center for Disease Control and Prevention had released a major review of 40 years of NHANES and vital statistics data. It found no associations between overall cancer mortality and any BMI category. While associations with cancers considered ‘obesity-related’ were slightly higher, they were lower for others, leaving no higher deaths from cancers overall. “Our results showed little or no association of excess all-cancer mortality with any of the BMI categories. None of the estimates of excess deaths was statistically significantly different [from null],” the researchers concluded.

The same month as the WCRF report, the results of the Million Women Study were published [reviewed here], examining the risks for 17 cancers and mortality associated with BMI. Despite its epidemiological shortcomings, it was still unable to find any tenable correlations between any BMI category and incidences of all cancers. The splitting hairs version found, like the CDC, some cancers hugged null on one side and others on the other, leaving no overall difference.

In other words, the news reporting that obesity increases the risk for 6 cancers was a test of reading comprehension skills: it didn’t tell you about the other 11 cancers.

Where is a Dr. Chapman when we need one?

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