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Old 03-08-2012
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Biochemistry Source of glucose in low carb diet!

41 y.o. male with BMI:42 tries to lose weight by diet with very small amount of carb and normal protein and fat for 2 weeks. Drinks 1 glass of red wine each day.
lab: glucose:75
What is the most likely source of his majority of plasma glucose.
A. amino acid
b. ethanol
c. fatty acid
d. glycerol
e. purine

Ans: D
I thought amino acid is always the main source for gluconeogenesis???
even in starvation?
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can anyone figure this one out?
is the glycerol major source only because his BMI is 41?
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Quote:
Originally Posted by kenlee View Post
can anyone figure this one out?
is the glycerol major source only because his BMI is 41?
The big boy still eats a normal amount of fat....

Fat has 9 calories in it versus 4 cal in carbs and protein.

And yeah, the body fat determines the time of survival in the periods of starvation.
Muscles are spared for later...
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Quote:
Originally Posted by DocSikorski View Post
The big boy still eats a normal amount of fat....

Fat has 9 calories in it versus 4 cal in carbs and protein.

And yeah, the body fat determines the time of survival in the periods of starvation.
Muscles are spared for later...
so normally its majorly amino acid for gluconeogenesis even in starvation.
In significant obesity it is majorly glycerol(fat) for gluconeogenesis.
is this what you are saying?
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Originally Posted by kenlee View Post
so normally its majorly amino acid for gluconeogenesis even in starvation.
In significant obesity it is majorly glycerol(fat) for gluconeogenesis.
is this what you are saying?
I think its fat all the time.

I think in starvation, (like running a marathon, but way slower) first glucagon is depleted, than gluckogenesis kicks in (from fat mostly) and finally at the end its muscles that are breaking down to provide substrate for gluconeogenesis.

So the amount of body fat will actually be determining the survival and functioning of the body till final muscle-wasting stage
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Ok so this is what's going on over here.

1st week during fasting/starvation it will be purely amino acids. After the 1st week the body starts breaking down fats and converts to glucose.

Now over here if you read the stem there are 2 things going on. Normal protein intake and in the second week. Since normal protein intake it is being converted to the glucose and not much amino acid breakdown of muscle is required. Now he is in the second week, and here the majority of glucose is from glycerol from fat.

So answer D.
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Quote:
Originally Posted by kenlee View Post
so normally its majorly amino acid for gluconeogenesis even in starvation.
In significant obesity it is majorly glycerol(fat) for gluconeogenesis.
is this what you are saying?
That is exactly correct

If this were a healthy person then the major source of glucose would have been amino acids.

Please correct me if I am mistaken .

Thanks.
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1st week - muscle goes
after that - fat goes

this is why you don't overtrain, you'll just be eating up the muscle you are trying to build

getBIG.
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Quote:
Originally Posted by Dr.NickRiviera View Post
1st week - muscle goes
after that - fat goes

this is why you don't overtrain, you'll just be eating up the muscle you are trying to build

getBIG.
Not if you are eating normal amount of protein.

getSkinny.
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Not if you are eating normal amount of protein.

getSkinny.
yea but there'll come a time where ur protein absorption plateaus and then theres nothing to support the increased energy demand other than your muscles, so theyll get broken down.

getSkinny (and fat) seems to be the motto for usmle studying
but after step its right back to getBIG!
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Quote:
Originally Posted by Dr.NickRiviera View Post
yea but there'll come a time where ur protein absorption plateaus and then theres nothing to support the increased energy demand other than your muscles, so theyll get broken down.

getSkinny (and fat) seems to be the motto for usmle studying
but after step its right back to getBIG!
true that!

We hear these "5 step program super diet - lose 10 pounds per day" on tv - they are all based on the simple trick that delusional housewifes believe in - they make you lose muscle, which goes away pretty fast if you stop protein supply.
But I think if you keep fat and protein going, but cut down carbs - you save the muscle, but start burning fat.
Its more or less close to that Atkins diet where people only eat protein and no carbs or fat.

So as this chubby guy with BMI 42 will stop eating carbs, he will start losing weight over these 2 weeks. This will be actually healthy...

=======

To prove this, this is what they say to obese patients 2 weeks before surgery - "Stop eating carbs".
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Quote:
Originally Posted by DocSikorski View Post
true that!

We hear these "5 step program super diet - lose 10 pounds per day" on tv - they are all based on the simple trick that delusional housewifes believe in - they make you lose muscle, which goes away pretty fast if you stop protein supply.
But I think if you keep fat and protein going, but cut down carbs - you save the muscle, but start burning fat.
Its more or less close to that Atkins diet where people only eat protein and no carbs or fat.

So as this chubby guy with BMI 42 will stop eating carbs, he will start losing weight over these 2 weeks. This will be actually healthy...

=======

To prove this, this is what they say to obese patients 2 weeks before surgery - "Stop eating carbs".
studies show that no carb diets have crazy rebound weight gain though
i dont know what the mechanism is
but we deffo avoid the whole 'no carbs' approach in the fitness world.
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Quote:
Originally Posted by Dr.NickRiviera View Post
studies show that no carb diets have crazy rebound weight gain though
i dont know what the mechanism is
but we deffo avoid the whole 'no carbs' approach in the fitness world.
Because you will feel to tired to go pump that iron.
Carbs would provide quick source of glucose for your excersising muscle instead of going into gluconeogenesis after glycogen is depleted.

But we deffo avoid getting big in the hipster world

Lol

By not eating carbs
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But we deffo avoid getting big in the hipster world

Lol

By not eating carbs
"jeans so skinny you'd think i starve my fabric".
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