Glycogen and fat stores??

Prayforya

So, I was reading on this post about weights vs cardio and somebody said something about weights first to burn glycogen and then cardio to hit up the stored fat. Sounds great, but how do you know when you're finished with the glycogen and have moved into the fat deposits?? Is it a time thing? Reps?

Anybody can help?

BrianSharpe

Bro-science.

If you ever fully depleted your glycogen stores you'd know it - you'd hit the wall so hard that you'd bounce.

Pretty much all cardio burns a certain amount of fat as fuel. The low intensity so-called "fat burning zone" burns the highest proportion of fat as fuel but, compared to the training or cardio zone, burns a lower number of calories and does not build cardiovascular health / endurance to the same extent as the more intense zones.

SteveTries

Bro-science.

If you ever fully depleted your glycogen stores you'd know it - you'd hit the wall so hard that you'd bounce.

Pretty much all cardio burns a certain amount of fat as fuel. The low intensity so-called "fat burning zone" burns the highest proportion of fat as fuel but, compared to the training or cardio zone, burns a lower number of calories and does not build cardiovascular health / endurance to the same extent as the more intense zones.

The "fat burning" zone also burns less total fat per minute than cardio zone. It's utterly useless.

grinch031

Weights are anaerobic so they use more glycogen than cardio which is aerobic and uses more fat and less glycogen (glucose). But its not one or the other, but there's always a ratio of fat vs. glucose being used for energy.

Yeah and when glycogen is depleted, you will be physically unable to continue working out because your brain will need what little glucose is available and gluconeogenesis will occur to break down protein into glucose and this is too inefficient to continue maintaining any kind of intensity. It is a terrible feeling that you can't confuse for mild fatigue.

UponThisRock

Worrying about where your fuel might be coming from during a workout is a waste of time.

Meaningful fat loss occurs because of a calorie deficit over days/weeks/months

iplayoutside19

Worrying about where your fuel might be coming from during a workout is a waste of time.

Meaningful fat loss occurs because of a calorie deficit over days/weeks/months

This^

There might be an ultra-runner or epic cyclists around MFP that may have depleted their glycogen enough to burn fat, but I'm betting 99% of MFPer's will never approach this point.

Focus on your nutrition, and bust it at whatever you do for a workout and you'll be fine.

waldo56

That said, if you are running and running only, especially on a treadmill, you should be able to feel when your body shifts the fuel mixture to primarily fat, as your run will get harder, how much so depends on what sort of shape you are in. Sprinters talk about walls, your average beginner runner will hit the wall and switch over to fat almost exclusively in the 2nd mile. The better a runner you become, the more fat you will burn from the get go and the longer your glycogen will last (for use as needed, powering up a hill and a sprint finish for example).

All higher intensity exercise requires glycogen and will use it mostly.

I'm sure burning off some glycogen first will help change the fuel ratio to mostly fat sooner, but the same effect comes from getting in good cardio shape, especially if you know how to pace yourself (as opposed to just setting the machine to a set speed for a half an hour).

waldo56

Worrying about where your fuel might be coming from during a workout is a waste of time.

Meaningful fat loss occurs because of a calorie deficit over days/weeks/months

This^

There might be an ultra-runner or epic cyclists around MFP that may have depleted their glycogen enough to burn fat, but I'm betting 99% of MFPer's will never approach this point.

Focus on your nutrition, and bust it at whatever you do for a workout and you'll be fine.

? The body burns mostly fat during cardio workouts ?

Total glycogen depletion and the body burning mostly fat, saving its glycogen, are two completely different things.

When you are running on the treadmill, it all of a sudden gets harder, you look down in fear as you realize you've gone a mile and have 3 more to go, you worry but push through the moment hoping for the best....congratulations, you just felt your body kick over to burning 99% fat for fuel, and as long as you can sustain it now, the situation should remain relatively static for a long time, until your legs begin to truly fatigue. And since your body is saving a reserve of glycogen, feel free to crank the speed up for the final 1/8 mile and finish strong, speeding up should actually make the run easier at that point since you will kick the glycogen burn back in.

grinch031

Worrying about where your fuel might be coming from during a workout is a waste of time.

Meaningful fat loss occurs because of a calorie deficit over days/weeks/months

This^

There might be an ultra-runner or epic cyclists around MFP that may have depleted their glycogen enough to burn fat, but I'm betting 99% of MFPer's will never approach this point.

Focus on your nutrition, and bust it at whatever for workout endevour is and you'll be fine.

Any endurance athlete on a ketogenic diet after several weeks of adaptation will burn primarily fat during their distance workouts even at higher intensities. Their ratio of fat to carbs is always high because they don't have carbs available to burn and their body has adapted both muscularly (using mostly fat) and the brain (to primarily be fueled by ketones).

But like UponThisRock said, it really doesn't matter in the grand scheme of things where your fuel is coming from because it all evens out at the end of the day. In order to not burn glucose you must deprive yourself of glucose, so you end up eating more fat so that you can burn more fat.

Prayforya

Worrying about where your fuel might be coming from during a workout is a waste of time.

Meaningful fat loss occurs because of a calorie deficit over days/weeks/months

This^

There might be an ultra-runner or epic cyclists around MFP that may have depleted their glycogen enough to burn fat, but I'm betting 99% of MFPer's will never approach this point.

Focus on your nutrition, and bust it at whatever for workout endevour is and you'll be fine.

Any endurance athlete on a ketogenic diet after several weeks of adaptation will burn primarily fat during their distance workouts even at higher intensities. Their ratio of fat to carbs is always high because they don't have carbs available to burn and their body has adapted both muscularly (using mostly fat) and the brain (to primarily be fueled by ketones).

But like UponThisRock said, it really doesn't matter in the grand scheme of things where your fuel is coming from because it all evens out at the end of the day. In order to not burn glucose you must deprive yourself of glucose, so you end up eating more fat so that you can burn more fat.

Thanks yall (Yes, I'm a Texan) for all the worthwhile info!

Child369

As a runner, I know focus primarily on heart rate. Bikers and runners keep their heart rate in specific zones. Fat burning zone is possible with a lactate threshold test. Hope that helps!

VMarkV

It's much easier to deplete glycogen with aerobic activity than anaerobic activity
Google Lyle McDonald glycogen