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The Holy Grail of Weight Loss
What’s the di erence between fat- and sugarburning metabolisms? Find out with Dr. Jonny Bowden.
“Burn more fat!”
It’s the goal of every weight-loss program and the promise of every infomercial. And no wonder. Who doesn’t love the visual image of unwanted belly, hip and thigh fat being incinerated into oblivion?
But what does “fat burning” actually mean? And why is it so hard to accomplish?
First things first. Your body uses two primary sources of fuel: fats and carbs. Under normal, resting conditions, most of your energy comes from fat. The mix changes as soon as you start to move. If you’re sitting on the couch, you’re burning about one calorie per minute, most of which comes from fat. But if you get up from the couch and walk to the kitchen to get some chips, the ratio starts to change slightly. The percentage of the calories you’re burning from fat goes down and the percentage of calories you’re burning from carbs goes up.
If, instead of walking to the kitchen, you decide to sprint 15 minutes to and from the corner store to get those chips, then things change a lot. The number of calories you burn goes way up (compared to sitting on the couch), the proportion of those calories coming from fat goes way down, and the proportion of those calories coming from sugar goes up considerably.
How do we know this? Because we can measure it, using a metric known as respiratory quotient, which tells you how many of the calories you’re burning during exercise are coming from fat. In the early days of Equinox, we had a metabolic lab, where I worked with the world-renowned ultramarathoner and exercise