There is nothing like data to reverse long-standing beliefs about what is, or isn't, good to eat. For years now, we have been bombarded with warnings from self-appointed nutritional gurus telling us about the dangers of eating carbohydrates. A quick scan of Internet postings, books, media reports and testimonials will convince anyone that approaching a loaf of bread holds the same danger as getting near a hungry crocodile. Variations of this theme include, that if you eat that slice of bread your brain turns to mush, your body becomes a sinkhole of inflammation, you will develop instant diabetes, and a size XXL will be too small. Indeed, seemingly whole continents of people have turned away from carbohydrates as a result. They are following diets last eaten in the Stone Age before cavemen crawled out of their caves and developed agriculture. If asked, these folk will tell anyone willing to listen that according to their scientifically impeccable sources, not eating carbohydrates will allow them to live forever, or at least a very long life.
Alas, it is not so.
One of the best ways to see what foods correlate with a long life is to examine what thousands of people have eaten over the past thirty years, and how their longevity has been affected by their diet. During the first week of January, a study appeared in JAMA Internal Medicine vanquishing the belief that all carbohydrates are nutritionally evil. Researchers from the Harvard School of Public Health looked at the diets of more than 74,000 women from the Nurses' Health Study and more than 43,000 men from the Health Professionals Follow-Up study. These volunteers filled out questionnaires about their diets every two or four years from the mid-1980s to 2010. It turns out that those people who ate whole grain carbohydrates had a 9 percent lower overall mortality rate and up to 15 percent lower cardiovascular-related mortality (death from heart disease and strokes). (1)
The U.S. Department of Agriculture has been telling us for years to increase our consumption of brown rice, whole wheat bread, high fiber cereals, and other grains like buckwheat (kasha), quinoa, oatmeal, and even cornmeal. But their pronouncements don't make it into celebrity-based magazines, wine bar conversations, nor onto the bestseller book lists. And since their recommendations have to be based on science, not hype and science fiction, they are rather dull in comparison to a diet announced in a tabloid. But according to the Harvard researchers, replacing just one serving of red meat per day with one serving of whole grains decreased death from heart disease by 20 percent. (2) This recommendation is compelling even if it does contradict those who claim that eating a diet of red meat will lead to long life.
One of the nice things about epidemiological evidence is that it is not a hostage to transient changes in lifestyle. Someone on the fad diet of the month claims immediate improvements in appearance, energy and cognition. Young women are saying that their skin is suddenly smooth, their hair is shiny, and they are getting skinny after drinking beef broth. Others are claiming that their brains are so charged after imbibing caffeine laced with melted butter that they must start writing their Nobel prize acceptance speech. If these changes are indeed real, they will withstand the test of time and be present 20 years from now.
In the meantime, the JAMA study has told us how to live a longer, healthier life. Why not start now with a piece of whole wheat toast?