On Wed, 26 Jul 2000, Amadeus Schmidt wrote:

> Here we are again in a protein amount discussion. :-)

everyone needs a hobby.

> As a look at paleo food sources shows, nutrient which is hardest to get
> is food *energy*.

I agree with this.

> Therefore in paleo times due to shortage of energy some more protein must
> have been used calorically. It doesn't seem as if this caused any adaption
> so that protein burning was more healthy. It looks as if the human body just
> can bear the additional stress (this may be an adaption).

I think it's an open question whether we have become adapted to a
greater utilization of protein for energy, or for other reasons.
If Pauling is correct, for example, we are able to take advantage
of large amounts of dietary lysine to keep arteries clear.  These
levels of lysine are not available with RDA protein amounts.

> >A trained person adds much more than red cells.  He or she adds
> >muscle, in significant amounts, and that muscle needs a
> >continuous blood supply.
>
> I don't know which increased blood volume you assume. I suppose not
> the doubled (14 liters). However, the amino acid pool is in the blood,
> it's capacity will be a funtion of the volume.
> If you assume a body builder at 10.5 liters (50% more!) than the blood can
> hold 55 + 50% = 83g. This determines the maximum capacity of one meal
> if it was *empty*.

Remember that 70kg is only an average body weight to begin with.
My weight, at the moment, is just over 100kg.  My LBM is about
84kg.  So even assuming a sedentary lifestyle (false, these
days), I'd need a minimum of 84g/day of protein.

> >Protein-requirement ..  We can survive on fairly low levels,
> >but to me the evidence suggests that we flourish with higher
> >levels.
>
> Or maybe we flourish only, because most micro nutrients are associated with
> the protein part of various food items. And *this* is what we need.

Protein foods are generally nutritious, I agree.

> You assume "increased maintenance" from workouts. It's possible that muscle
> cells need more "repair" because of more free radical damage
> (more oxygen throuput).
> There may be more cell deaths leading to decomposition of the whole
> apparatus. As far as reusing amino acids is "not 100% efficient" a actual
> increased demand of is then to be assumed. And could be measured as nitrogen
> loss.
> I think, The total amount should be related to the 40g loss which is
> measured for the whole normal body functions.
> I can hardly imagine that workout may double the turnover rate.

Why not?  You've given some very good reasons here.  It's well
documented that exercise increases free radical load, and the
efficiency of amino acid reuse may itself be subject to
degradation for the same reason.  Amino acid use requires
enzymes, and enzymes are proteins too.  I can easily imagine that
the stresses to which cells are subjected during intense exertion
could simultaneously increase demand for amino acids and reduce
the efficiency of their recycling.  And this would be consistent
with exercisers' *felt* need for significantly more protein.

> So claims Philipp, that he "needed" it.

Precisely.  You may try the experiment yourself.  Start a program
of high-intensity weight training three times a week, but keep
your protein intake at about RDA level.  See how you feel after
two or three weeks of this.

Todd Moody
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