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This year, the results of a metastudy came out that seemed to identify high-protein diets as a cause of early death. That's bad news for Atkins and paleo people - but is the study reliable?

This March, a study published in reputable journal Cell Metabolism. Titled 'Low Protein Intake Is Associated with a Major Reduction in IGF-1, Cancer, and Overall Mortality in the 65 and Younger but Not Older Population,' the study seemed to be saying that if we want to live longer, we should eat less protein, particularly less animal protein. That flies in the face of the currently-fashionable high protein diets like Atkins, Paleo and the broader primal approach to eating. The study said that people under 65 who ate high protein diets were at increased risk of overall mortality, of cancer, and even of diabetes. While that sounds counter-intuitive - protein is slowly absorbed and highly thermogenic, with a tenth to a quarter of its caloric content turned to heat during the process of metabolizing it for use as a fuel, so sugar seems a likelier culprit for a diabetes spike that threatens leave up to a third of us needing medical supervision for type II diabetes. Still, you can't argue with the figures.

Is eating red meat is as dangerous as smoking 20 cigarettes a day?

You can argue with the headlines, though, and when you get headlines that tell you eating red meat is as dangerous as smoking 20 cigarettes a day - which is pretty dangerous, I might add - it seems closer examination is called for.

While Paleo advocates questioned the result other writers and commentators had a field day. After all, it's the news vegetarians, vegans and adherents to low-fat, low-proein diets have been waiting for. The Guardian's Holly Baxter penned a column on March 5 warning, 'it's time to kick the high-protein habit - before it kills you.' Hard words - and while Baxter raised some important points in her column, like questioning how it could be that 39% of women are on a diet 'most of the time,' she also took the opportunity to take some wild slashes at Atkins and especially at Paleo, which she referred to as based on 'sketchy pseudo-scientific claims, and overall it's hard to take the import of her words seriously.

Eating red meat, she told us then, is 'as harmful to your health as other vices like smoking.'

The study that caused the furore wasn't quite so emphatic. Being a scientific work without an ax to grind it reported its findings in the staid language of the laboratory. 'We combined an epidemiological study of 6,381 US men and women aged 50 and above from NHANES III, the only nationally representative dietary survey in the United States, with mouse and cellular studies to understand the link between the level and source of proteins and amino acids, aging, diseases, and mortality,' the study says.

And that's where we hit our first major stumbling block.

Reliability of The NHANES Study

The NHANES (National Health And Nutrition Examination Survey) study was based on self-reported data from a very large sample who were tracked over a 24-hour period and their bloodwork done. Then the sample was followed for the next 18 years via their medical records, to see if they died. 

The problem with this approach can best be summed up by one Jack Winkler, former professor of nutrition policy at London Metropolitan University.

Winkler calls the data obtained in the study 'lies.'

He elaborates: 'they did a correlation between the national diet survey in the United States (NHANES), and some data on death by disease. They linked it up, then alleged that protein caused death. Now, NHANES suffers from what all diet surveys suffer, namely: you ask people what they eat and what you get back is lies. People respond normatively. They put themselves in the best possible light. They're not harmful, deceitful lies. In the case of the British survey, people underreport how much they eat by 25% and adolescents by 30%. Underreporting they call it, but in plain English, it's lies.'

So NHANES data can't be trusted. Why didn't the Cell Metabolism study use different data? 

Because none was available.

Continue reading after recommendations

  • The Cell Metabolism study: The Holly Baxter article in the Guardian: What's wrong with NHANES? Professor Jack Winkler's comments: The NHS comments:

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