The Secret of a Healthy Diet? Believe in what you’re eating!
A look at the mysterious power of the placebo effect and the role the mind can play on our bodies.
First doctor: “This morning for breakfast he requested something called ‘wheat germ, organic honey and tiger’s milk.’”
Fans of Woody Allen may recognize this snippet of dialogue from his 1973 film, Sleeper. The story revolves around a health-food store owner who, for some reason, is cryogenically frozen in 1973, and then thawed out 200 years later. Of course, everything in the world has changed dramatically. The country has become a police state, the local MacDonald’s restaurant claims to have sold trillions of hamburgers (ho, ho, ho) – and, worst of all, everything he had been telling his customers was nutritious, is now thought to be really unhealthy and dangerous.
For moviegoers that last bit caused plenty of chuckles. But then Woody Allen fans included people who would have been interested in food controversies. For example, advice that eggs raise cholesterol, or salt raises blood pressure or that coffee gives you cancer. All of these were official advice for a while, and all became suspect later.
This see-sawing of scientific opinion has seen ‘fat-free’ foods going from being a virtuous public health initiative to being reinterpreted as a deeply suspect and cynical marketing tool, sneakily used to sell sugary breakfast cereals and snacks. You couldn’t make it up! Or, as the food writer, Gary Taubes, has said, “Diet is a trade-off: we put the whole country on a low-fat diet, and, lo and behold, we have an obesity epidemic.”
Now obesity is certainly a very real health problem, one that affects millions of people all over the world, in both rich and not-so-rich countries. But as for low-fat diets, a major American study concluded in 2006 that their health benefits were greatly overrated, and specifically that they had no effect on the risk of heart disease or cancer. It’s been a similar story for low-cholesterol advice. Eggs are now considered perfectly healthy.
Or take gluten. It’s a protein found in wheat, barley, and rye. Apparently authoritative experts (or at least internet sites) warn that no less than 55 diseases have been linked to gluten, and that as many as one in six people may be gluten intolerant. They add that 99% of the people who have gluten intolerance are never diagnosed – leaving the impression that whatever your problem, gluten just might be the reason for it. End result, today, millions of people are following gluten-free diets and sales of ‘gluten-free’ have taken off, reaching a staggering US15 billion in 2016 – and making some food companies very happy.
However, gluten intolerance can be tested, and it turns out that the vast majority of people avoiding it don’t seem to need to. Less than one percent of the U.S. population, for example, suffers from celiac disease whereby eating gluten triggers an autoimmune response that damages the intestines and keeps nutrients from being absorbed properly.
But here’s where food allergies gets interesting: many people who go gluten-free feel better even though they don’t have celiac disease. What’s more, as Joseph Murray, a prominent gastroenterologist, and author of a book on gluten has noted: “when they go back to eating wheat they feel worse again.”
How can this be? Well, one practical reason is simply that when people give up gluten they end up eating less of anything. And for people with digestive problems, eating less can make them feel better.
But there’s a psychological explanation too. Peter Gibson at Monash University in Australia conducted a study in which people were given high-gluten, low-gluten, and no-gluten – placebo – diets, without knowing which they were on. All of the diets, even the no-gluten one, caused intestinal problems – and to a similar degree.
Placebos are things that make you feel better even though they contain no active ingredients. In this case, the patients were being made to feel worse despite there being no reason: a ‘nocebo’ effect. People expected to feel worse on the diet, and so they did.
The psychiatrist, Laurence Kirmayer, has taken this idea further and places placebos within a symbolic and ritual healing frame. ‘Placebo effects have broader social roots through word of mouth, advertising and popular culture.’ In other words, if everyone around you is saying salt gives you headaches, then it quite likely will do so. Researchers have also found that paying more for the medicine – or the anti allergy food – or even packing it in certain colors, can increase its ‘power’ in the eyes of the patient. Amazingly, ‘sham’ acupuncture and even sham surgery has been shown to produce results not only as good as the ‘real thing’ but even a little bit better!
The same kind of psychological thing seems to apply to diet regimes – ones like the so-called Paleolithic diet. This rests on two big no-nos: no dairy products and no grains as the diet assumes that the body can’t digest them because such foods didn’t exist in prehistoric times. It’s lousy science not least because archaeological evidence indicates Stone Age Man actually ate grains and because the body can acquire lactose tolerance, the ability to digest dairy foods, in just a few generations. Plus, some peoples that lack the enzyme to digest milk, have bacteria in the stomach that do the job instead.
But that doesn’t mean the diet doesn’t work. As long as people believe in their new regime, they can obtain very real and measurable benefits! Quite how the mind really affects the body remains mysterious, but what research has shown that the effects can be dramatic. So sip a herbal tea or tuck into wheat germ and organic honey… if it works for you!