American Fitness Professionals & Associates

By: Dennis M. Loya, BS.,JD.,
Certified Personal Trainer

 Some people believe that the best way to lose body fat is to exercise at a low intensity for an extended period of time this is affectionately known as “The Fat Burning Zone”. If you believe in this urban legend that just will not die, I am sure you believe in the Loch Ness Monster, Santa Claus, Bigfoot, and the Abominable Snowman. “The Fat Burning Zone” is a mysterious pace determined by obscure heart rate formulas that tell you exactly where you should be exercising in order to burn the most fat.

The secret to losing weight is to burn more calories than you take in. Losing body fat and keeping it off permanently requires a carefully planned exercise program that features aerobic and anaerobic workouts, as well as careful attention to nutrition. When you eat healthy, supplement properly, and participate in a reasonable exercise program which incorporates a combination of training then you can enjoy permanent fitness and weight-loss benefits. The foregoing is easy in principle only. We would not have a multi-billion dollar fitness gadget industry if losing weight were easy.

The truth is science currently has not been able to determine the exact moment during exercise when we switch from burning calories from carbohydrates to burning fat reserves. Even if it were to be determined where this “Fat Burning Zone” exists it would merely be a ballpark figure because it would be different for everyone. Moreover, the idea of the “Fat Burning Zone” (hereinafter referred to as FBZ), is a misinterpretation of the body’s energy systems. Fat is used for fuel during exercise at a variety of intensity levels. However, at rest the body’s preferred fuel is fat, add exercise to the mix and the body burns a combination of glucose and fat at different percentages.

FBZ is a vernacular expression, for what exercise professionals refer to as the beta oxidation of fatty acids. At any given time, you are burning or oxidizing fuel (food), that is breaking down for energy. The food you eat gets taken apart by the body, and broken down to fatty acids, amino acids and glucose which provides energy to the body to do everything it needs to do. That means providing energy to breathe, grow hair and nails, digest food, think, and sleep.

The greatest proportion of fuel comes from fat when the body is at rest. But the total number of calories burned is small. What happens when you begin to exercise the fuel split changes and carbohydrates start to contribute a slightly greater percentage of the fuel and fat becomes the smaller percentage. But the harder the exercise, the greater the total number of calories per minute are expended. Although, the percentage from fat decreases the total number of calories expended increases.

Exercising at a higher level of intensity has a lot of benefits. For one thing, it increases your aerobic capacity and conditions your heart. Moreover, it burns a ton of calories, makes you fitter and better conditioned, and being more conditioned makes you a more efficient fat burner during the non-exercising hours. Raising your Basil Metabolic Rate (BMR) which increases your overall caloric burn and combined with healthy nutrition and rest, will help you burn more fat even at rest. That is right you are going to burn more calories when you are playing the Game Cube.

Now for the science in simplistic terms that crushes the Urban Legend. Exercising at 60% of your age predicted maximum heart rate (APMHR), which is calculated 220 - current age, for 30 minutes may burn 200 calories. Of these 200 calories, 50% may come from stored fats. Thus 100 calories will come from fat, the rest of the calories will be from carbohydrates.

However, exercising at 80% of your APMHR for the same time period may burn 500 calories. Of this only 40% may come from fats, the rest from carbohydrates. Therefore you would burn a total of 200 calories from body fat at a lower percentage. The higher the intensity of your workout the less fat you burn by percentage. This is your body’s fastest way of getting more oxygen to exercising muscles.

Weight management is one of the reasons so many Americans take up exercise, for women this is at the top of the list. The percentage of calories you burn from fat does not matter. For weight-loss, the important number is how many TOTAL calories you burn. Just maybe we should forget about labels such as “fat burning”, the important thing is to work up a good sweat, stay within a target training zone, be safe and have some fun.

My disclaimer: I do not recommend undertaking any new exercise or diet program without getting solid medical advice from a trained professional. While what I am going to tell you will probably come under the heading of “common sense”, if your client knows or even suspects they have some unique health circumstance, encourage them to talk to their Doctor first.

Copyright © 2003 by Dennis M. Loya, JD.

All rights reserved. Except for use in a review, the reproduction or utilization of this work in any form or by any electronic, mechanical, or other means, now known or hereafter invented, including xerography, photocopying, and recording, and in any information storage and retrieval system, is forbidden without the written permission of the author. Author Biography

Dennis M. Loya, JD. is owner of IronWerks™, a personal training service that focuses on weight loss, nutrition, sport specific and condition specific training serving the beautiful Newport Beach/Corona Del Mar area of Southern California. Dennis has a law degree from American College of Law, and is a Certified Personal Trainer through the International Fitness Professionals Association (IFPA) and National Personal Training Institute (NPTI) and is a AMFPT and NPTI Certified Sports Nutritionist. Dennis has been involved in training and health related issues for over 25 years. As a trainer, he specializes in physique transformation, exercise for pregnant women, and sport-specific strength training preparation. IronWerks™ web site can be found at http://www.fitnessresultsnow.com/ the phone number is 949.278.3875 and any correspondence can be sent to:

IronWerks™ Personal Training
Attn.: Dennis Loya
1000 W. MacArthur Blvd. #21
Santa Ana, CA 92707