Some additions:

I wrote:

>Each gram of this carbs will have to stop at pyruvate level then.
>And obviously there's a different pathway, which can convert glucose into
>fat, without use of the pdc (Pyruvate decarboxylation complex).
>
>Even if *this* pathway doesn't exist,  ...

A pathway from glucose to fat circumventing the blocked pyruvate stage
*does* exist. Some fatty acid is constructed out of actetyl CoA, that means
through the normal pyruvate stage. A different pathway exists (the pentose
shunt pathway). Using this (anerobic) pathway the body can (in the liver)
synthesize triglyceride without using pyruvate (and the pdc) from glucose.

Quote:
<<about 30% of glucose is oxidized in shunt in the liver with "lots of lipid
biosynthesis">>

Means: if the glucose can't be (fully) metabolized the usual way (Citric
acid cycle) there *is* a way, the body can make fat out of it.
And use that fat later on.

Todd:
>>But there are plenty of obese people who take large
>>multi-vitamin supplements, including the B vitamins, who
>>nevertheless remain obese.
>Somehow the usual supplements don't seem to make it. Why?

It came to my mind, that this missing reason why supplements don't work may
be that only such molekules have been recognized as "vitamins", which show
serious diseases, if absent. Like thiamin and niacin.
However, every living cell from bacteria over plant to humans contains such
pyruvate decarboxylase. This means every uncoocked unprocessed food had it,
since all existance of any animals.
In this way, it's more astounding that animals can synthesize
some of the substances (like alpha lipoic acid) anyway, instead of deriving
them from the food. Ready made, gigantic molekules larger than a ribosome.
They are certainly difficuly to be synthesized themselves.

If the abilities to synthesize missing substances by alternate pathways is
limited in some way, then it won't be sufficient to supply only the
absulute essentials.

The answer is: living food.
Carbohydrate food in its natural condition.

Or tissues as food, which are equipped to metabolize other carbohydrates.
Like yeast is (very much). Meat is too (from pork). It has a rather limited
amount of decarboxylation capacity, but is itself so low in carbs, that it
can equal out a little of other carbohydrate.
Will take amounts.

regards

Amadeus S.
"Eat as naked with a stick and a stone"