The Fat burning zone myth

[RayCr]

The fat-burning zone is the most misunderstood and perpetuated myth in weight loss. Overweight people studiously and lethargically plodding away in be 'fat-burning zone' hardly raising a sweat in the belief that they are burning away their fat. Well, yes and no.  The focus should be on burning calories, not just 'fat calories'. Endlessly grinding away at 50% effort burns relatively few calories. Certainly too few to make any meaningful weightless. There are 7,700kcals (kcal=calorie) worth of energy in 1kg of fat. That means in order to burn 1kg of fat, you must have a calorie deficit of 7,700. A 70kg person probably burns at most 400kcals in one hour in the 'fat burning' zone.  That's 20 hours' worth of exercise or 3 hours a day!   Compare this with all those religiously doing their prescribed 20 minutes a day!  Totally meaningless.  

Like most things in life, the harder you work, the better result.  Wright loss a no different 

[Heybales]

And the fact that after awhile the exercise in that HR zone may no longer be a workout for the heart and lungs - so it stops being much of a benefit for the time spent.

And for the day as a whole it doesn't matter what the energy source was during the workout.

I mean - it's better than sitting on the couch true, but it's not the workout it could be if you are spending the time anyway.

Also, while the % of fat burned to carbs may be highest in that zone compared to working harder - if that is the idea desired - don't workout at all and just sit around burning upwards of 90% fat as energy source.

Yes, do a good workout for your goals - cardiovascular improvement, strength training, whatever - and cause your calorie deficit to burn fat by eating less than you burn in total.

[Glenda]

Exercise every day is critical for good health.  It has little to do with weight.  What you weigh depends on what you eat, just to be clear.  Exercise is so important for better health it is important to find some way to enjoy it.  I read today that it is bad to hold on on a treadmill.  HA !  I read on my treadmill and I will always hold on no matter what they say about that.  I have no health problems and I am 78 but of course exercise or not I could get cancer or something.  But I really believe exercise goes a long way in keeping you healthy.  Maybe for some dancing or cycling could be long term???

[phoslin]

Thanks for the insights guys, I was wondering why they have such a low heart rate for the 'fat burning' zone - It is intuitively a pretty ineffective heart rate target.   

[Heybales]

Very true - the cardiovascular system for many people can make some big initial improvements.

While just starting exercise it might be possible to rocket right past that zone and feel like you are dying - it doesn't take much low level effort (usually) to have some improvements and then it doesn't feel too hard to be in that zone, and not feel like dying being above it.

It's one of those cases where the same level of work (effort, intensity, ect) soon causes a lower HR.

Shows how calorie burn from HR-based formula can be whacked out.

Massive burn above reality reported when really unfit, to perhaps below reality reported after getting fit.