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Dr. Darrell White's Personal Blog

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Musings on “Exercise as Medicine”

The “exercise is medicine” movement is kind of a confusing thing. On the one hand we in CrossFit are the uber example of how exercise as an independent variable can enhance health. On the other we have the “Big Sugar” industry funding research and promoting the notion that exercise is all that you need, that there is no effect of nutrition on health. Train your way out of any kind of diet, if you will. This has led to the toxic effect of “BS” industry money supporting academic research that is in effect little more than marketing for their products. (Visit TheRussells.CrossFit.com for details). Indeed, the soda industry in particular has come in for some very pointed criticism which includes being accused of acting like the tobacco industry ( https://blogs.scientificamerican.com/food-matters/if-soda-companies-don-t-want-to-be-treated-like-tobacco-companies-they-need-to-stop-acting-like-them/ ). Pretty harsh, but probably deserved.

Here’s the rub: exercise really is a medicine equivalent for a very large number of medical problems. Heck, if it were only to work for cardiovascular health and Type 2 diabetes it would be considered, or should be considered, a miracle treatment. Not only that, but exercise very well might work independently of diet. While exercise should not be used as an excuse to consume a poor, dangerous diet, you may actually be able to at least partly out-train a poor diet to at least some degree.

In 2009 a study was published in the International Journal of Epidemiology (http://m.ije.oxfordjournals.org/content/39/1/197.full) examining the effect of aerobic exercise on longevity (hat tip to Michael Joyner, MD at Mayo). Mind you, the study was enrolled prior to the creation of the CrossFit fitness program (completed in 2003), so the definition of fitness (aerobic health) will be viewed as incomplete by CrossFitters since it includes only aerobic fitness. In addition, what is defined as an unhealthy diet would only partially pass muster here; we would agree that simple carbohydrates (sugars) are unhealthy, but there is a plethora of more recent data that strongly suggests that red meat and healthy fat do not render a diet worrisome in the least.

A careful reading of the study revealed a couple of nuggets that should not surprise even a little bit. Eating the unhealthiest diet was associated with a 40% increase in all-cause mortality in comparison with the healthiest diet. Those who ate that worst diet and reported that they did moderate or greater levels of exercise had a 13.5% decrease in mortality. That group of bad eaters who exercised and were proven on a modified cardiac stress test to actually have greater aerobic fitness levels had a 55% decrease in mortality. Let that sink in for a minute: people who ate a shitty diet who exercised to the degree that they were fit by the testing criteria in the study were half as likely to die in any period than those who were unfit.


Frankly, I don’t care who funded this study. Eating a shitty diet that is high in sugar increases your risk of death by 40%. Proof. Exercise that produces improved fitness, even fitness that I would view as partial or incomplete, reduces all-cause mortality in people who eat a diet high in sugar by more than half. Proof. Yeah, sure, I get that this could be used to justify or excuse eating that way, but the reality has always been that most people don’t exercise at all. Nada. Bupkis. Those who do certainly don’t achieve much in the way of any kind of fitness because they don’t exercise effectively—saying you exercise only got you a 15% decrease in mortality, after all. These results only apply if you get fitness results, and let’s face it, working hard at exercise is not the default setting in the developed world. By comparison eating better is a breeze.

Studies such as this one are mint, man. Especially to people like me, people who follow the CrossFit Rx and other programs that ask you to work hard. It’s exercise AND nutrition. Says so in the study. Sure, we can pick at this one if we want, like I did above, but my bid is that we use studies such as this one as talking points to prove that our worldview is the gold standard by which all public health initiatives ought to be compared. We can turn the cynical “exercise is medicine” campaign of “BS” on its head and use their own data against them. Eat like a CrossFitter (protein, nuts and seeds, little starch, no sugar). Exercise like a CrossFitter (functional movements performed at relatively high intensity). Seek ever-higher levels of fitness (work capacity across broad time and modal domains) like we do.

“Exercise is medicine” is just fine as long as we continue to call BS on “BS”. Health requires both exercise AND nutrition. People who are fit, especially physicians, are just the right people to tell that story.


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