★How Exercise Improves Your Gut Health

One thing I really hate about apps like MapMyRun is the way they insist on counting calories. There is nothing more disheartening than feeling totally victorious after a 3-mile run, only to see that you’ve basically burned off the equivalent of the kids’ leftover grilled cheese crusts that you crammed in your mouth last night.

In fact, counting calories burned during workouts is so depressing that I find it counter-productive. I’m less likely to keep going if I have a calorie count flashing in my face and more likely to work harder and longer for less measurable benefits, like getting a sparring combination right or finishing a group workout strong.

And as it turns out, the benefits of exercise are much more extensive than merely burning calories. The old adage “calories in, calories out” isn’t really accurate at all in light of our growing understanding of the human microbiome. Paying attention to what we eat is more important than slavish adherence to calorie counts. Likewise, the effects of exercise extend beyond heart health and into the gut, according to a recent article in the New York Times.

Most of these changes were not shared from one person to the next. Everyone’s gut responded uniquely to exercise.

But there were some similarities, the researchers found. In particular, they noted widespread increases in certain microbes that can help to produce substances called short-chain fatty acids. These fatty acids are believed to aid in reducing inflammation in the gut and the rest of the body. They also work to fight insulin resistance, a precursor to diabetes, and otherwise bolster our metabolisms.

Most of the volunteers had larger concentrations of these short-chain fatty acids in their intestines after exercise, along with the microbes that produce them.

The study was published in November in Medicine & Science in Sports & Exercise, and tracked changes in gut bacteria of volunteers who embarked on a new fitness routine for six weeks but kept their diet the same. The scientists then had the volunteers discontinue their exercise program for six weeks and found that the positive gut changes had disappeared, and the volunteers’ microbiomes had reverted to their pre-study states.

I find the results of this study particularly fascinating because it reflects a shift in thinking about our bodies as complicated and interconnected systems that combine to make a whole, rather than the overly simplified habit of treating our bodies as machines.

“Calories in, calories out” doesn’t reflect the reality of the human microbiome, nor the various ways the body systems are interdependent. Counting calories doesn’t take into account the need for vitamins, nutrients, fat, and protein, nor does measuring calories burned take into account the way the planes of movement interact with gravity to improve our balance and coordination. Simply eating less might help you lose weight, but it won’t help you cultivate healthy gut bacteria the way eating healthy and moving more will.

The reality is that our bodies aren’t machines, food isn’t merely fuel, and all exercise isn’t created equal. Variety in all things — especially food and movement — is the best way to keep your mind and body healthy.