Less and less energy is available through ingestion as you move up the food chain. This is known as Trophic Level Transfer Efficiency. Eating plant-based matter is as close as we can get to ingesting the full, raw energy of the sun. If you're devoted to HITT, you owe this energy to your workout.
Sinatra never sang about the large intestine—not that we know of, anyway. But like Frankie's beloved NYC, your gut is a crowded microbial metropolis whose tiny and pugnacious citizens whistle for taxis, order takeout at 3 in the morning, and generally live the high life. When jackasses from out of town show up to bring disorder, our bacterial buddies swarm and conquer, thanks to Inulin. Talk about a city that never sleeps!