When you don't get enough oxygen, you literally strangle your cells. It's like putting a noose around their necks, making it very difficult for them to do their job. As hard as they might try, they can't process food properly. They get bogged down, filled with sludge, and you, consequently, run out of energy.
You literally work at one fifth of your potential when you don't get enough oxygen. Your body slows down, gains weight, and becomes even more stubborn about changing.
Find out more about this book:Jumpstart Your Metabolism: How To Lose Weight By Changing The Way You Breathe