The myth of the Fat-buring Zone

ZyheeMoongazer

I just read an interesting article regarding the "Fat-burning Zone" and thought I would share.

http://www.active.com/triathlon/Articles/The-Myth-of-the-Fat-burning-Zone.htm

dlaplume2

I was thinking about this just two days ago. Thanks for sharing it was very helpful.

Amber82479

bump

shovav91

Thanks for sharing! Very interesting.

MaximalLife

I see value in both low impact, low intensity cardio as well as concentrated, extreme anaerobic interval training.
Couple the above with an effective program of resistance, and you have a solid program of body re-composition.

And all of this presupposes clean food intake.

I am striving for this ideal, and as good as my results have been, I want more.

This is it!

carlie_carl

Ive had better results from interval training, when I first started 11 months ago I would do 90 minutes on a crosstrainer or eliptical trainer as you US guys know it? it worked at first but my body adapted, now i do short sprints and different variations of interval training, that mixed with strengh training has made me see my ribs for the first time in my life!! and im no small guy, im in the process of bringing out my abbs, so sticking to the interval training to shed some body fat from my stomach

Geordiegal08

Excellent article...my workouts are about to change!!!

ninerbuff

I think the biggest interpretation here that needs to be understood is that you burn a higher PERCENTAGE of fat in low intensity cardio, rather than at higher intensities. It doesn't mean you will burn more fat overall. Good article.

A.C.E. Certified Personal Trainer
IDEA Fitness member
Kickboxing Certified Instructor
Been in fitness for 28+ years and have studied kinesiology and nutrition

Yanicka1

bump for later

grapenutSF

I think the biggest interpretation here that needs to be understood is that you burn a higher PERCENTAGE of fat in low intensity cardio, rather than at higher intensities. It doesn't mean you will burn more fat overall. Good article.

I'm confused by this comment. Would you mind clarifying?

My biggest take-home was that in the time AFTER the exercise--during recovery-- steady state doesn't do much whereas anaerobic/interval/weights does. Lovely to hear, reinforces what I'm doing anyway!

This is all very sensible to me, and I have no reason to doubt, but just curious how credible the source and author are...? Also, is the author any relation to Allwyn Cosgrove who helped design New Rules of Lifting workouts???

ninerbuff

I'm confused by this comment. Would you mind clarifying?

My biggest take-home was that in the time AFTER the exercise--during recovery-- steady state doesn't do much whereas anaerobic/interval/weights does. Lovely to hear, reinforces what I'm doing anyway!

This is all very sensible to me, and I have no reason to doubt, but just curious how credible the source and author are...? Also, is the author any relation to Allwyn Cosgrove who helped design New Rules of Lifting workouts???

If you did HIIT for 5 mins and and compared that with walking for 5 mins, the percent of fat burned based on the exercise is higher for walking than HIIT. HIIT burns glycogen stores first, then fat. Walking mostly burns fat and doesn't tap glycogen because the intensity is low. But HIIT burns more overall calories.
Also by raising your RMR, you burn much more fat at rest and HIIT and other high intensity workouts do this. Walking and low intensity exercise don't.

A.C.E. Certified Personal Trainer
IDEA Fitness member
Kickboxing Certified Instructor
Been in fitness for 28+ years and have studied kinesiology and nutrition

2fit4fat

sorry... whats HIT?

lsunderl

Really interesting... trying to get myself motivated to pick up those weights

grapenutSF

sorry... whats HIT?

HIIT=high intensity interval training

Thanks, ninerbuff, for the explanation!

Isunderl, need motivation? See this:

http://nerdfitness.com/blog/2011/07/21/meet-staci-your-new-powerlifting-super-hero/

heybales

I'm confused by this comment. Would you mind clarifying?

My biggest take-home was that in the time AFTER the exercise--during recovery-- steady state doesn't do much whereas anaerobic/interval/weights does. Lovely to hear, reinforces what I'm doing anyway!

Their reference was also outside the HIIT the article was talking about, I think referencing another myth.

Training at this lower "fat-burning zone" of say 60-70% MHR allows your body to use a majority of fat as energy, depending on fitness, perhaps 50%. But because your effort is so low, you only burn x amount of calories.

But if you just did your 20-40 min cardio at a higher "aerobic zone" of say 70-80% MHR, while you body may only be able to use 33% of the energy from fat, rest carbs, you are actually burning 1.5x amount of calories.

So just using some figures, and everyone's would be different values, but with the same principle.

Fat-burning zone for 30 min at 130 HR - 300 cal.
150 cal fat, 150 cal carbs. (50% fat)

High aerobic zone for 30 min at 160 HR - 500 cal.
165 cal fat, 335 cal carbs. (33% fat)

So while the percentage of fat burned went down, the actual amount of calories burned from fat went up, and of course your general calorie burn went up.

Just goes to show, if you only have 20-30 min for exercise - make it really count by doing higher zone, or the HIIT referenced in the article.

The fat-burning zone is great if you are at race weight already and need to train the body for 2+ hr endurance events.

Acg67

Summing Up the Research Findings

• In acute trials, fat oxidation during exercise tends to be higher in low-intensity treatments, but postexercise fat oxidation and/or energy expenditure tends to be higher in high-intensity treatments.
• Fed subjects consistently experience a greater thermic effect postexercise in both intensity ranges.
• In 24-hr trials, there is no difference in fat oxidation between the 2 types, pointing to a delayed rise in fat oxidation in the high-intensity groups which evens out the field.
• In long-term studies, both linear high-intensity and HIIT training is superior to lower intensities on the whole for maintaining and/or increasing cardiovascular fitness & lean mass, and are at least as effective, and according to some research, far better at reducing bodyfat.

http://alanaragon.com/myths-under-the-microscope-the-fat-burning-zone-fasted-cardio.html

heybales

If you did HIIT for 5 mins and and compared that with walking for 5 mins, the percent of fat burned based on the exercise is higher for walking than HIIT.

HIIT burns glycogen stores first, then fat. Walking mostly burns fat and doesn't tap glycogen because the intensity is low. But HIIT burns more overall calories.
Also by raising your RMR, you burn much more fat at rest and HIIT and other high intensity workouts do this. Walking and low intensity exercise don't.

Actually, just to be clear on this for folks that really are interested in getting into it.
Right on for percentage understanding, which is where most don't realize the difference.

The moments actually doing the high interval, into the anaerobic zone, would be carb burning, there would never be fat because fat requires oxygen, and the definition of anaerobic is without oxygen. The idea of HIIT is to get into that anaerobic zone.

Coming back to recovery level would be the same mixture of carb/fat that would normally occur, with the addition of the lactic acid just produced during the interval.

At total rest your system (unless insulin causes fat storage mode turned on) can do the almost total fat for energy, but as soon as you start moving, you start to approach that 50% mix.

So for folks using the HRM during HIIT, your calorie burn during the actual exercise will probably show a bit to a lot lower, because the short high HR doesn't avg out the long low HR during recovery to a decent avg that looks good.

But as you said, rest assured, you will burn more during the recovery after and all day long.

Even if you can't do HIIT, even if you can only walk, just raising the grade to something high for 30 sec, or striding really fast to that next light pole, can have great interval-like improvements.

runjenal

Thanks for posting. Training for a 1/2 marathon in April to raise $ for the Leukemia and Lymphoma society (http://pages.teamintraining.org/al/gulfcoa12/jenmccoy) and didn't lose a pound the first two months. Started focusing on diet with MFP and adding weight training. I know I will be stronger, be able to run faster and longer with these additions and less weight on my body. Thanks for posting a great article!

scottb81

On the other hand . . .

The advantage of training at a lower intensity for longer at first is that you can build a strong aerobic base and then after a number of months can train much longer at high intensities.

A question of short term vs. long term gain.

JennieAL

Summing Up the Research Findings

• In acute trials, fat oxidation during exercise tends to be higher in low-intensity treatments, but postexercise fat oxidation and/or energy expenditure tends to be higher in high-intensity treatments.
• Fed subjects consistently experience a greater thermic effect postexercise in both intensity ranges.
• In 24-hr trials, there is no difference in fat oxidation between the 2 types, pointing to a delayed rise in fat oxidation in the high-intensity groups which evens out the field.
• In long-term studies, both linear high-intensity and HIIT training is superior to lower intensities on the whole for maintaining and/or increasing cardiovascular fitness & lean mass, and are at least as effective, and according to some research, far better at reducing bodyfat.

http://alanaragon.com/myths-under-the-microscope-the-fat-burning-zone-fasted-cardio.html

• Fed subjects consistently experience a greater thermic effect postexercise in both intensity ranges.

So this goes in the face of the "fasted state" training that people are doing to maximize the fat loss?

heybales

• Fed subjects consistently experience a greater thermic effect postexercise in both intensity ranges.

So this goes in the face of the "fasted state" training that people are doing to maximize the fat loss?

That has more to do with the fact that in the morning, before you eat, you are in fat burning mode already, that's what you were doing all night, any insulin spikes turning on fat storage are long gone.

So low intensity exercise at this time just keeps using that same mode. Your body of course starts using glucose to burn the fat at higher intensities, exactly the same as it normally would.

What probably has been noticed, is that compared to having a high carb breakfast/snack first and insulin putting you into fat-storage mode, you burn more fat first off this way.

But you can cause the same thing and have a snack first, something with much lower carbs and higher fat/protein.

I never like early morning jogs on totally empty stomach.

heybales

I just read an interesting article regarding the "Fat-burning Zone" and thought I would share.

http://www.active.com/triathlon/Articles/The-Myth-of-the-Fat-burning-Zone.htm

Sadly, while a lot of other good explanation in there, there are tidbits that are wrong and have been debunked.

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Every pound of muscle you put on requires approximately 50 calories per day to maintain. This doesn't take into account the calories burned developing that muscle, or the calories burned while maintaining that muscle. These 50 calories are the amount needed by that muscle to just sit there.

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It's been shown in studies that a lb of fat takes 2 cal/day to maintain, muscle is 8 cal/day. One study has eluded to 35 potentially, but it is by itself.

So if you lose 50 lbs of fat, and just keep your current lean muscle, your BMR has gone down by 100 cal/day. And chances are the diet/exercise combo has actually caused some muscle loss. And carrying around less weight means less energy needed to do so, so less maintenance calories.

What a good reason to revisit the maintenance and goal figures in your profile/settings often.

Meggles63

So, if I'm very close to/at maintenance, and trying to preserve muscle, yet want to lower bf%, wouldn't it be better to work out in the "fat burning" zone rather than up in the higher zone?

Or does it matter?

heybales

So, if I'm very close to/at maintenance, and trying to preserve muscle, yet want to lower bf%, wouldn't it be better to work out in the "fat burning" zone rather than up in the higher zone?

If you want to make the most of your workout time available, if it is limited, then higher zone will be better.
You will burn slightly more fat calories, and more calories in general. But it's not like you are going through your glucose stores and tearing down muscle, unless you are going a long time.

Make sure to eat a good snack afterwards of even carbs/protein.
The carbs will go to replenish the glucose stores you just used, the protein to repair any muscle that needs strengthening.

If you are marathon/triathlon training and doing 2hrs plus for the workouts several days in a row, then yes the fat burning zone would be better. Because as you keep using up the glucose stores (about 2000 calories worth rough avg) and get close to running out, your body starts breaking down muscle to use the protein for energy to help burn the fat.

So too high a zone for this specific type of workout would be breaking down muscle.