Repeat a lie long enough and people start believing it, as Joseph Goebbels, Hitler’s propagandist-in-chief, once said. Medicine is full of lies – sorry, assumptions of dubious provenance – that everyone believes must be true but aren’t. We believe them because medicine is a science (discuss), and they wouldn’t just make this stuff up (oh no?)
Here are a few, and you probably believe some (if not all) of them yourself, but they’ve all been plucked out of the air by ‘expert committees.’
Eat your five-a-day
This exhorts us to eat five servings of fruit and vegetables every day. In truth, we should be eating more than that – but where did the idea of five come from? Apparently, it was conjured up in a meeting of fruit and vegetable companies in California in 1991. Strangely, representatives from McDonald’s were also there.
It seemed like a good way to sell more produce, but there wasn’t a lot of scientific evidence to support the recommendation. At least McDonald’s didn’t influence the group to include one Big Mac in the healthy eating guidelines – although Heinz succeeded.
Miffed that it hadn’t been invited to the party, Heinz got into the act a few years later, and since then its tomato ketchup has been included as a legitimate five-a-day option.
And it was confusing what it all meant. Is it three servings of vegetables and two of fruit, or five of each? And what is a serving, anyway? Nobody was sure on that one for years, but in the end everyone has settled on ‘a handful.’
When you’re obese
You cease to be overweight and become classified as obese when your body mass index (BMI) reaches 30.
But how did this precise line in the sand get drawn? It’s hard to track down its origin, but the likeliest suspect is the National Health and Nutritional Examination Study (NHANES), which started tracking the diets of a group of Americans in 1976.
It set the BMI for obesity at 32.3, which got the experts at the World Health Organization thinking that, perhaps, it would be better if it was more of a round figure. So, in 1995, it set the official obesity score at 30. As someone mentioned afterward, the score was “largely arbitrary,” which is a science-y way of saying it was made up.
Safe drinking
What’s a safe amount to drink? Nobody really knows because no country agrees with another. ‘Safe upper limits’ in the US are 196 grams (8.4 oz) of pure alcohol a week (that’s around 10 pints of beer or eight glasses of wine), while the world’s party poopers are, surprisingly, the French, who recommend we should consume just 100 grams (4.3 oz). If you really want to party, go to Japan, which has set its safe limits at 280 grams (12 oz).
But how did these figures come to exist in the first place? It can’t be science, because there’s no global agreement. A member of the UK’s Royal College of Physicians let the cat out of the bag after the group met in 1987 to set the nation’s safe limits, when he admitted the figures had been ‘plucked out of the air.’
Cholesterol and heart disease
The saturated fats we eat raise our ‘bad’ LDL cholesterol, and that blocks our arteries and causes heart disease. It’s a theory that launched the multibillion-dollar statin drug and low-fat food industries.
The trouble is that it’s never been proven, and inconvenient truths keep popping up that are sidelined as a paradox. Like the ‘French paradox,’ because the French eat large amounts of saturated fats and have lower rates of heart disease (roughly a quarter of that in the UK, for instance), or the ‘female paradox,’ because women naturally have far higher levels of cholesterol than men and are less likely to get cardiovascular disease.
Or that more than half of people who die from heart disease have normal cholesterol levels, while those with low cholesterol are 64 percent more likely to die prematurely.
So how did it come about? One of the major drivers of the cholesterol hypothesis was medical researcher Ancel Keys, whose famed ‘Seven Countries Study’ demonstrated a direct cause-and-effect relationship between eating saturated fats and heart disease. However, the association disappeared when you look at an earlier study of his, which included data from 22 countries.
So, keep repeating the same lie long enough… oh, and by the way, Joseph Goebbels never said that. It’s just another myth.
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