We know that overindulging in our favorite foods isn’t good for our health, but researchers propose a new way of quantifying just how harmful those treats can be.
Now that we’re in the midst of the holiday season, calorie-laden foods seem to be ubiquitous — sugary cookies, sweet candies and juicy hams dripping with honey. But in the holiday issue of the BMJ, researchers report that making a habit of overindulging in rich fare can take years off your life. In fact, the scientists calculated exactly how much our favorite foods can shorten our life span; eating red meat every day, for example, is linked to a loss of at least 30 minutes off of your life.
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Dr. David Spiegelhalter, a statistician at the University of Cambridge and author of the study, says that it’s not the occasional indulgence but consistent over-eating of certain foods that can impact your longevity. But for most people, weighing the immediate gratification of eating a steak sizzling on a plate in front of you against a far-off loss of a year or two of your life in your 70s or 80s, almost always ends with people favoring the steak. So he decided to frame daily diet choices in the more immediate terms of adding or losing hours to your day. Calculating that the average life spans about 80 years, he divided that time up for adults 35 and older into nearly a million half hours, and assigned each 30 minute period to be 1 microlife. Each microlife is about one millionth of life expectancy after age 35. He then assessed how unhealthy eating habits would impact a person’s total microlives.
Smoking, for example, eats up approximately 10 microlives for every 20 cigarettes smoked — or about 15 fewer minutes of life expectancy per cigarette. “Smoking 20 cigarettes a day (10 microlives) is as if you are rushing towards your death at 29 hours a day instead of 24,” he says.
Averaged over a lifetime, the following habits are linked to the loss of one microlife: smoking two cigarettes, eating a burger, being roughly 11 pounds overweight, chugging a second or third alcoholic beverage, and watching two hours of television.
On the positive side, behaviors that can add half hours of life expectancy include: drinking 2-3 cups of coffee or taking statins, cholesterol-lowering drugs (one microlife), eating fruits and vegetables (four microlives), and working out 20 minutes per day (two microlives).
On a demographic level, gender can also afford some advantage; just being a woman is associated with gaining 4 microlives a day, while male gender is roughly equivalent to smoking eight cigarettes every day (not clear why, but possibly due to the fact that women may tend to eat healthier overall than men). Living in Sweden as opposed to being a resident of Russia is associated with a gain of 21 microlives daily for men (a trend that may be attributed to the higher rate of alcohol consumption and lower rates of physical activity in Russia). And while it may be obvious that people are living longer now than they were a century ago, framing that argument in microlives reveals a gain of 21 microlives for men living in 2010 compared to 1910 (15 a day).
So far, says Spiegelhalter, the tallies for additional microlives and those for lost microlives are not interchangeable; a microlife lost to drinking an extra beer, for example, isn’t gained back by exercising for 20 minutes. The idea is to engage in as many additive behaviors as possible to ensure they outpace the microlives you lose.
Of course, microlives can only be a gross measure of how lifestyle can impact longevity, and Spiegelhalter acknowledges that people’s bodies respond differently to harmful or beneficial behaviors.
But overall, the Cambridge statistician argues that simpler ways to remind people that every choice they make in their daily lives can affect their longevity may help them to adopt healthier habits more readily. “One does not need a study to conclude that people do not generally like the idea of getting older faster,” Spiegelhalter wrote.