The 3 Biggest Myths About Fat-Burning For Active Women

Another great article from by Dr. Susan Kleiner
I am really angry. I have spent my entire career firmly planted in the field of sports nutrition, where the goals are performance-based.
In sports nutrition, weight-loss is an outcome of enhancing physical performance, not a goal unto itself.
 That’s why I wanted to write about the 3 biggest myths perpetuated by the diet world in regards to the best ways to burn fat for active women.


Myth 1

The best way to burn fat off your body is to exercise in the fat-burning zone.

Also known as sub max­i­mal exer­cise, or train­ing at 45 to 65% of your VO2max, this mod­er­ate exer­cise inten­si­ty depends on a mix of about 55% fat to 45% carbs, and requires a mod­er­ate amount of total calo­ries per minute of exer­cise.

While you cer­tain­ly burn more fat than car­bo­hy­drate dur­ing the exer­cise ses­sion, the total calo­rie burn is pri­mar­i­ly depen­dent on the dura­tion of the train­ing ses­sion.

There is not much post-exer­cise ele­va­tion in meta­bol­ic rate, or “after-burn” of calo­ries.

On the oth­er hand, high inten­si­ty exer­cise, 70% and high­er of your VO2max, requires at least 72% of the total calo­ries burned to come from car­bo­hy­drates, and the high­er the inten­si­ty, the more your body depends on car­bo­hy­drates, rather than fat, for fuel.

In fact, with­out enough car­bo­hy­drate on board, you can’t reach this lev­el of train­ing inten­si­ty and work out­put.

More to the point of this dis­cus­sion, high inten­si­ty exer­cise leads to a high­ly ele­vat­ed post-exer­cise meta­bol­ic rate, or after-burn. And that after-burn can last for 24–36 hours, and is typ­i­cal­ly fueled most­ly by fat.

This is where body sculpt­ing hap­pens.

By exer­cis­ing in the high­er zones that depend on carbs, not fat, you increase your total calo­rie and fat burn­ing for many hours after exer­cise.

You get the best train­ing effect, enhanced per­for­mance, and a lean physique by burn­ing the most carbs dur­ing exer­cise, and that’s the sci­ence of it!


Myth 2

To lose more fat, eat a low carb diet.

You just learned in Myth #1 that it’s train­ing in the carb-burn­ing zone, not the fat burn­ing zone, which real­ly dri­ves fat loss.

If you don’t fuel your body with enough carbs to dri­ve high inten­si­ty exer­cise, you’ll per­ceive that you’re train­ing very hard, but in real­i­ty you won’t be any­where near that lev­el of inten­si­ty; it just feels like it.

So to real­ly burn off fat, you must fuel your train­ing with the carbs you need to achieve high inten­si­ty ranges of exer­cise, and then refu­el for recov­ery to train hard again lat­er that day, or the next day.

To lose more fat, you need more carbs to fuel your train­ing.


Myth 3

To lose a pound of fat per week, lower your calories by at least 500 per day from your energy requirement.

This has been the advice of the diet world for­ev­er, but you know as well as I do that it doesn’t work that way.

Some weeks you lose a pound, some weeks you lose half a pound, some weeks you don’t lose any­thing! And over time, you plateau. Why? Because your body is a dynam­ic organ­ism, not a sta­t­ic machine!

Research has shown that a deficit of more than approx­i­mate­ly 300 calories/day sends sig­nals to your brain to slow down your meta­bol­ic rate, just in case the world is run­ning out of food.

Your body begins to con­serve fuel, and slows the rate at which it will allow you to burn it. How­ev­er, the same research showed that you can fake your brain and body out if you keep your ener­gy deficit to only about 300 calo­ries. This keeps you burn­ing calo­ries at a high­er rate.

So, if you eat only 300 calo­ries less than your needs you will lose more weight than if you low­ered your calo­rie intake by 500 calo­ries.

You real­ly can eat more to weigh less. Not to men­tion hav­ing enough ener­gy to train hard, and ben­e­fit from the increased fat burn­ing machin­ery that is your body.


In sum­ma­ry, fol­low­ing the truths of sci­ence rather than the myths of the diet world will fuel your body, mind and spir­it. Pass it on!!


Writ­ten by Dr. Susan Klein­er


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