“The researchers isolated this bacterial strain from elite runners, put it into the colons of lab mice and found that these human-derived bacteria boosted the mouse’s performance on a treadmill exertion test by 13%.” NPR: Elite Runners’ Gut Microbe Makes Mice More Athletic — Could It Help The Rest Of Us? (If you carry this out far enough, the endgame becomes pretty clear. Eventually, the sedentary people are going to eat the athletic people.)