Can you increase fat oxidation with specific forms of exercise?
Ahh … the age-old question: can you actually train, trick, or tip your body into some kind of enhanced fat-burning mode, sucking fat cells off your butt, thighs, and tummy more rapidly?
You’re about to discover the answer.
This topic came to the forefront of my attention when I noted a recent study, Rethinking the role of fat oxidation: substrate utilisation during high-intensity interval training in well-trained and recreationally trained runners. I know that’s a mouthful, but the study itself wasn’t too difficult to grasp.
The goal of the researchers was to look into the degree to which the rate of fat oxidation could be altered by training. In other words: can your exercise choice or exercise history affect the rate at which you burn fat?
Before we look into what the researchers discovered, allow me to make an important clarification: the title of this episode is not “Which diet causes you to burn more fat?” Why? Because we already know the answer, and I’ve given the nitty-gritty details in my two-part article series called How To Turn Yourself Into A Fat Burning Machine, in which I report on a University of Connecticut study that conclusively proved a high-fat, low carbohydrate diet could increase fat oxidation from an average maximum of 1.0 grams per minute to over 1.7 grams per minute.
But let’s say that you’re already not eating too many calories, but you’re also “being careful” with your carbohydrate intake and not engaging in a diet rich in foods such as processed starches, high fructose corn syrup, sugar, and other foods that can cause frequent fluctuations in blood glucose and a decrease in fat oxidation (an effect I describe in detail in How To Lose Fat Quickly). Can your training or a specific way of training also increase fat oxidation?
In this most recent study, researchers compared fat and carbohydrate oxidation rates using something called indirect calorimetry, in which you breathe in and out of a mask that measures oxygen consumed and carbon dioxide produced to give an approximation of your fuel use. Two different sets of subjects were measured while they exercised, with high-intensity interval training. Set one was comprised of well-trained, seasoned runners, and set two was comprised of slightly less well-trained recreational runners. The actual workout consisted of six, four-minute long running bouts separated by two minute recovery periods on a treadmill set at a 5% incline.
The researchers found that, despite similar ratings of perceived exertion, blood lactic acid, and carbohydrate burning rates, the well-trained runners performed much better on the workout (no surprises there!) but also had a nearly threefold higher rate in fat oxidation! So not only were they burning more calories overall, but they were burning an enormously higher percentage of those calories as fat.