Fat-Burning Zone The Overrated Weight Loss Approach

Hey there!

How you going? This is T.C. back and back from my holiday break in Singapore. Had my fair share of bad food and back to my own training. Hey got to enjoy some nice food on a holiday. BTW, hope you’re doing awesome with your workout routine and getting closer to your dream body.

Just recently, I was training one of my kick ass clients who was wearing her Polar heart rate watch and the watch was beeping about 5 minutes or less into the 30 minutes personal training session. I told her that the watch is going to beep throughout the 30 minutes. The reason been that the 30 minutes workout is high intense and the Polar watch was set to beep when she is working out of the fat-burning zone. Can’t remember what was the exact conversation but that watch beeping got us talking about the fat-burning zone.

So What is The Fat-Burning Zone?

If you ever being to any of those fitness centres in Perth, you might see this chart above on an exercise bike or Cross-trainer (or eliptical) machines right on the control panel. The Fat-Burning Cardio Zone is basically the zone where the body burns the most amount of fat in percentage. And you would think that’s where you should be when you run or ride your exercise bike if your aim is to lose weight. If you look at the chart above again, the pink area is where you want to stay in if you want to stay in the recommended fat-burning zone. It’s quite low intensity and an easy pace to maintain. You see I was one of those personal trainers that recommend my clients to stay in the fat-burning zone when they’re on the cardio machines at least 45 minutes 3 times a week if they aim to lose weight.

So Can the Fat-Burning Zone Help You Lose Weight?

I would say the Fat-Burning Cardio Zone just doesn’t cut it in weight loss. I gotten a few emails from people I don’t know personally sometimes telling me why they just can’t shift the weight after all the walking every day at the park for months. And walking is definitely an exercise activity that most people engaged in at the fat-burning zone. In fact, sitting on a couch would probably be burning more fat at a higher percentage than walking. The thing is our body used fat and carbohydrates as the main fuel and very little protein. At higher intensity level, the body will used more of the carbohydrates fuel and at lower intensity the body will used more fat. Simply, the selection of the type of fuel we used is based on the intensity of the activities we engaged in.

And most people would think it make sense that to lose weight we should engage in the fat-burning zone because the more fat we burn the more weight we lose. Unfortunately, my practical experience in personal training tells me that people who put in the least effort (meaning working out at a low intensity) lose the least weight or no weight at all and there’s a quite a few studies that seem to show slow and steady fat-burning zone cardio yields the least weight loss results.

Have a look at the study below,

In a 12 month study done to see the effects of a recommended weight loss guidelines of 6 days a week of 60 minutes slow-steady state cardio each day on 202 subjects , it is found that the men on the average lost only 1.8kg and women lost only 1.4kg in that 12 month. Source: McTiernan A, Sorensen B, Melinda L, Morgan A. et al: Exercise Effects on Weight and Body Fat in Men and Women. Journal of Obesity. 2007;15: 1496–1512.

In an Australian study done in University of New South Wales, 12 young female subjects were put on a steady-state exercise (meaning they were in the “Fat-Burning Zone” intensity) for 15 weeks and the group was found to gain 10.5% abdominal fat. Source: Trapp EG, Chisholm DJ, Freund J, Boutcher SH: The Effects of High-Intensity Intermittent Exercise Training on Fat Loss and Fasting Insulin Levels of Young Women. International Journal of Obesity. 2008;32, 684-691.

In a 6 month study, 35 overweight people were divided to two groups with one group having a 25% reduction in calorie intake and the other group were having 12.5% reduction in calorie plus 12.5% increase in exercise expenditure by performing 5 days of 50 minutes aerobic activities. There was no additional effects of the “Fat-Burning Zone” aerobic exercise on body composition when compared to the group of subjects who were on the 25% calorie reduction programme. The fat distribution was no different. Source: Redman LM, Heilbronn LK, Martin CK, Alfonso A. et al; Effect of Calorie Restriction with or without Exercise on Body Composition and Fat Distribution. Journal of Clinical Endocrinolog & Metabolism. 2007; 92: 865-872

The Common Misconception of the “Fat-Burning Zone”

Like I mentioned, most people thought that the more fat you burn the more weight you lose. It’s like quite like that unfortunately. If it’s the case, I would recommend all my clients to sit on the chair when they come to me for personal training. The problem with “Fat-Burning Zone” exercise is that it does not burn much calories and to lose weight you do need to burn a lot of calories. Here’s a great example I adapted from one of my favourite read, The Body Fat Solution: Five Principles for Burning Fat, Building Lean Muscles, Ending Emotional Eating, and Maintaining Your Perfect Weight.

Fat-Burning Zone Exercise (30 Minutes)

Fuel Used: 50% fat, 50% carbs

Carbs Expended: 110 calories

Fat Expended: 110 calories

Total Calories Expended: 220 calories

High-Intensity Exercise (30 Minutes)

Fuel Used: 33% fat, 67% carbs

Carbs Expended: 222 calories

Fat Expended: 110 calories

Total Calories Expended: 332 calories

If you look at the chart above comparing the Fat-Burning Zone exercise with High Intensity Exercise, the fat fuel amount used can be similar but the big difference is the total amount of calories used.

Doing “Fat-Burning Zone” Cardio is Trading in your Time for Calories to Force a Energy Deficit to Promote Weight Loss

BTW, don’t get me wrong…I don’t mean that you can’t lose weight using the “Fat-Burning Zone” approach. I believe you can if you have the time to do heaps of them like few hours a day. It is accumulating calories through expending your time to force the weight loss. Remember from the research I quoted the subjects’ bodyweight was hardly shifting after doing like 5 to 6 days of “Fat-Burning Zone” aerobics activities for 1 bloody year.

Is it sustainable? I know it’s not for me. I got heaps of stuff to do. I’m sure you do. Unlike High-Intensity Interval Training (HIIT), Fat-Burning Zone cardio does not increase much of your metabolism. Therefore, what you burn in terms of calories in that exercise bout is what you get.