HIIT is often praised as being uniquely effective for fat loss—more so than LISS or steady-state cardio. That’s mainly on the basis that your body continues to burn calories at an accelerated rate after the workout is over. The size of this “afterburn effect,” as well as the extent to which it contributes to weight loss, however, have both been highly exaggerated.
Researchers from Colorado State University, for example, found that HIIT led to an average of 226 extra calories being burned over the course of the day. And that’s not just the calories burned after the workout. It’s the calories burned both during and after exercise. What’s more, HIIT had no impact on resting metabolism when it was measured 23 hours after exercise. All of the calories were burned during and immediately after the workout itself.