Fat Burning Zone
Fact or Myth?

If you have ever been on a treadmill, elliptical, or exercise bike, you will notice that the display panel offers you a variety of programs to fight the flab or perhaps more properly put, get your cardio on. It makes you wonder which way is best, right?

Perhaps the program that entices the most is “the fat burning" workout. Who doesn’t want to burn fat? Isn’t that the main reason most of us are even on the machine in the first place? After all, we are simply trying to get aerobic exercise and improve our health. It shouldn’t have to be rocket science. Which program is best?

IGNORE THE FAT BURNING PROGRAM
Virtually every piece of cardio equipment at the gym has a continuous-paced "fat burning" program on the display panel that promises to help you stay "in the fat burning zone." Unfortunately, this program is based more on myth than it is reality.

My advice to you is to ignore that program and here’s why: The belief that long, slow workouts are always better for weight loss than faster, shorter workouts is simply a case of missing the forest for the trees. TRUTH: The best fat burning workout plan is simply the one that burns the most calories. Whether the calories come from fats or carbs is pretty much irrelevant.

At the risk of getting just a tad sciency, I am going to pull facts from my AFAA Personal Fitness Trainer Theory and Practice textbook in hopes of explaining this somewhat confusing issue. I promise to make this as painless as possible, so please bear with me for a minute, and hopefully the angels will sing as the light flips on in your beautiful brain as you become enlightened with this cool info!

FAT VERSUS CARBOHYDRATE UTILIZATION
“ATP is the energy molecule that is present in every cell of our body. Any energy stored in the body in the form of carbs or fat must first be converted into ATP before it can be used. At rest, ATP is produced by the breakdown of both carbs and fat in approximately equal measure. The average person burns about 1 calorie per minute at rest, and about 50% of this calorie is supplied from carbohydrate; the other 50% of the calorie comes from fat. During low- to moderate-intensity exercise, this 50:50 ratio persists, as both fat and carbohydrate is burned fairly evenly for fuel.”

Here is where it gets interesting: “As the level of intensity increases, changes occur that begin to inhibit the use of fats and increase the use of carbs. A significant inhibitor is the lactic acid produced. Also, a person’s aerobic fitness level determines the point at which the cardiorespiratory system can no longer supply sufficient oxygen. At higher intensities, less and less fat is used as fuel, and more and more carbs are therefore used for energy production.”

GET THIS: “It should be noted that for clients with weight management issues, it is most important to burn large numbers of calories, creating a negative energy balance. It is not correct to suggest that a client train at a lower intensity in order to burn more fat. This suggestion will result in the client simply burning fewer total calories, even though a greater percentage of fat is expended at lower intensities.”

Herein lies the confusion: People often mistakenly believe using higher percentages of fat as fuel equals quicker fat loss. That is simply NOT TRUE! In reality, the more calories you burn, the closer you’ll get to your weight-loss goals, regardless of what type of fuel your body uses for energy.

PUTTING THE SCIENCE INTO PERSPECTIVE
Say you do 30 minutes of moderate-intensity exercise on a treadmill at about 40-60% of your Heart Rate Reserve (HRR). You burned a total of 146 calories with 73 (50%) of them coming from carbs and 73 (50%) from fat.

Now let’s say you do 30 minutes at a higher intensity, more like about 60-85% of your HRR, this time burning a total of 206 calories with 124 (60%) coming from carbs and 82 (40%) from fat.

Are the angels getting your attention right about now? They should be! Let’s sing it together, people! Hallelujah! The light bulb should be fully illuminated! Woohoo! It's about total calories, not which fuel source is providing them, when it comes to weight loss! Got it???

CAVEAT: Beginners or very deconditioned people may need to start out as low as 30-40% HRR and progress slowly over a few weeks’ time.

For people who have limitations preventing them from increasing exercise intensity, the continuous pace of long, steady workouts will provide the same weight loss benefits due to calorie expenditure as shorter, harder workouts; the workouts will just need to last longer, i.e., 50-60 minutes versus 30. This is perfect for elderly, obese, arthritis, low fitness level, etc., or if you just want to slow down enough to smell the roses and give your body a break from the demands of high-intensity exercise.

The point is, if you can you should push that intensity level up and keep it there for a better calorie burn in less time and more weight loss! I suggest mixing it up with a couple of interval training cardio sessions per week, a couple of continuous low-to-moderate, and a couple of high intensity.

For more info on starting a cardiovascular fitness routine go to Straightforwardfitness.com and for info on Target Heart Rates (THR) and Heart Rate Reserve (HRR) and how to figure yours, go to Target Heart Rate. While you are there click on over to the cardio benefits page because there is a whole lot more to gain from regular cardiovascular exercise than weight loss! What are you waiting for? Go get get your cardio on!

DISCLAIMER: Always check with your doctor before starting any exercise plan.

Linda Burke, CPT