He's also become a firm believer in structure: Eating at roughly the same time every day, and getting plenty of sleep to recover from workouts and to allow your body to keep its hormones in check. Finally, don't let small, inevitable setbacks get to your head, he says. "Hell, just this December I gained 15 pounds in one month. It's just a bump in the road. Nobody succeeds without failures."
What does a HIIT workout look like? You could jog for two minutes, sprint for one minute, jog for two minutes, sprint for one minute. Or you could do a HIIT workout on a bike, or by running up stairs and then jogging back down. The key is that you go relatively all out for a short period of time, then recover by maintaining a moderate level of intensity, then go again.