Is Fat Rocket Fuel for Runners?

Covering 26.2 miles is impressive no matter how fast you run, but those who excel have a secret weapon: the ability to burn fat for fuel. Scientists at Shanghai University of Sport followed elite male runners in their 20s and 30s before and after running a sub-three-hour marathon. Their metabolism of carbs and fats increased post-race, showing their bodies can switch from using readily accessible carbs to harder-to-tap lipids for energy. That matters because your body can only store so many carbs, which is why many runners “bonk” around Mile 20. To make the switch, under-fuel yourself with carbs on long training runs, forcing your body to tap into fat reserves for energy, and consider a higher-fat diet. In a separate study, eating a diet of 71 percent fat (like the keto diet) for six months led to a 50 percent increase in elite runners’ ability to metabolize fat.