Thu, Sep-16-04, 20:00
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Registered Member
Posts: 151
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Plan: low low carb
Stats: 142/146/148
BF:?/?/22%
Progress: 67%
Location: Brisbane, Australia
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Quote:
Originally Posted by mps
I'll reply because it seems like the question is interesting to some...
The short answer is no, they are not the same.
Ketosis occurs when there is incomplete oxidation of fatty acids. As long as enough carbohydrate is available, fats will be burned completely.
Excerise uses energy at a higher rate than when you are just sitting around but it does not produces energy in a fundamentaly different way.
If you are already in a fat-burning state, you will most likely burn a higher percentage of fat during the workout. But it depends somewhat on the type of work also. Anaerobic, high intensity will use ATP/CP pathways first, then glycogen, then fat.
Just sitting around you're burning mostly fat. Low intesity your buring mostly fat.
This does not mean that low intensity is better for buring fat however. You may burn more calories during high intensity training, both during and after the activity, and therefore end up with more of a calorie deficit and thus more fat buring over the course of the day.
Ketosis is mostly a function of lack of carbohydrate not induced by training. The exception is that if you do a workout that depletes glycogen you will then have less carbohydrate in your body and may go into ketosis faster than if you had not worked out.
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Now I'm confused again. I posted a question on a recent 'metabolic advantage of low carb' thread about whether there was a difference between ketosis (exercise or dietarily induced) and burning FFA's in your mitochondria without a ketone in sight. Somebody replied with quotes from some biochem texts which stated quite clearly that FFA metabolism directly in your mitochondria is a quite distinct metabolic energy pathway to ketosis. They both end up using acetyl CoA in cells, but get there via different metabolic pathways. Ketosis is very inefficient, which makes it such a star turn for weightloss, whereas free fatty acid burning in mitochondria is a very clean burn. Particularly because direct FFA metabolism in cells does not produce lactate as a by product as glycogen does. Both metabolize fat of course, just differently. So can you be burning just fat for energy, no glycogen, and not be in ketosis at all, particularly when you low carb long term? MPS and Built, HELP!
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