Intermittent Fasting and Muscle Cannibalism
Vowder
Posts: 378 Member
I don't IF at all with the exception of a nightly IF from 8:00pm through to about 8:00am.
Now, while I think I understand Keto fairly well, what I don't understand is:
Isn't muscle more readily available?
Why, when on KETO, am I not losing a ton of muscle. My losses appear to be about 85% fat. To be fair however, I am working out an awful lot these days.
Down about 85 with 15 to go for phase I.
Phase II will be an additional 20-30. Haven't decided yet.
Thanks for any help. Technical answers really appreciated.
Now, while I think I understand Keto fairly well, what I don't understand is:
Isn't muscle more readily available?
Why, when on KETO, am I not losing a ton of muscle. My losses appear to be about 85% fat. To be fair however, I am working out an awful lot these days.
Down about 85 with 15 to go for phase I.
Phase II will be an additional 20-30. Haven't decided yet.
Thanks for any help. Technical answers really appreciated.
1
Replies
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Not sure I understand the question, but here's what happens to muscles during a fast:
And here's what happens during keto:
Obviously more protein catabolism with fasting. Catabolism during keto is pretty much limited to the first 3 weeks, depending on protein intake of course.1 -
My question is:
During a fast your body still needs energy. Getting energy from muscle is easier than getting it from fat. Why, while in keto, doesn't your body get that energy by cannabilizing muscle?1 -
My question is:
(...) Getting energy from muscle is easier than getting it from fat. (...)
Where did you get this notion from? It defies any logic. Cause if it was true, your body would have cannibalized your muscle mass long before you lost your extra fat. Aka you'd be dead.
If you have any good sources for this claim, I'd be interested to know. Thx.1 -
My question is:
During a fast your body still needs energy. Getting energy from muscle is easier than getting it from fat. Why, while in keto, doesn't your body get that energy by cannabilizing muscle?
It's about glucose, ketones, and your brain. Your brain is the most metabolically active organ -- about 500 kcal/day.
It normally gets all of that from glucose -- about 125 g/d.
So what happens when you shut off the glucose (fasting)? Your body makes it's own glucose. It can covert protein to glucose at something like 1.6g protein -> 1g glucose.
If your brain continued to need 125 g/d glucose, your body would have to catabolize 200 g/d of muscle tissue to make it. About 1/2 lb per day. Your muscles would quickly waste away and you'd die.
So we evolved a way for the brain to burn an alternative fuel -- ketones. Ketones can supply all but about 160 kcal/day of our energy needs. We still need 40 g/d glucose.
Fat = triglycerides. 3 molecules of fatty acid held together with one molecule of glycerol.
We can use that glycerol to make glucose. About 1/2 of our needs (20 g/d). The rest has to come from protein.
So, during a fast, we continue to catabolize about 20-25 g/d of protein. That comes from muscle.
During a keto diet, we need the same about of protein to burn, but it comes from our diet. The rest of the protein we eat helps maintain our muscle mass. And we live happily ever after.
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Okay. What you are saying makes sense. I was misinformed or misunderstood.
Good. Thx.0 -
@wabmester Excellent explanation... even my brain comprehended it! These formulas stump me most times. 2
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@wabmester Excellent explanation... even my brain comprehended it! These formulas stump me most times.
I'm with you and I love being able to read information from some of the much more educated about the facts than I...2
