I've been trying to read up more about food combining, and I hear so many
conflicting arguments that I don't know which to follow.  I have been
avoiding mixing protein and starches for a month now, and I don't really see
a difference.  If anybody can sort out these arguments below, I'd appreciate
it.  Or I am considering to buy a few food combining books if this is too
complicated to explain.  If anyone knows of any good books that discuss the
topics below, please let me know.

[edited posts taken from sci.med.nutrition]
*********
> Actually, I might have misunderstood the whole term 'food combining'
> and I only used it as an example of one fad, not as a particularly
> easy to do fad. My friend in question uses a method in which she
> does not eat large amounts of proteins and carbohydrates during the
> same meal

    The reason for not eating concentrated proteins and concentrated
starches in the same meal is inherent in our digestive biochemistry.
Starches/carbos are digested in an alkaline or neutral medium, and
concentrated proteins are digested in a highly acid medium.  Since
alkaline/neutral and highly acid can NOT coexist in the same
stomach/intestinal system at the same time, such combinations, pandemic
in cultural diets the world over, can not be properly digested.  That's
why it is suggested to eat concentrated proteins with lots of
non-starchy vegs, OR eat concentrated starches (grains, pasta, roots,
...) with lots of non-starchy vegs.    Fruits, since their chemistry is
very different than other foods, should be eaten alone, as a complete
meal.  These simple rules will eliminate intestinal gas and poor
digestion.  Eating the best quality foods is meaningless, unless they
are digested properly. (1)

> (or something to that effect as I tried to understand why
> does not eating vegetables consitute as eating carbohydrates as one
> can mix them - in this particular diet - with meat proteins).

    If what you are referring to is food combining for 'amino acid
complementarity'; this is a myth propagated by Francis Lappe, in her
Diet for a Small Planet and has been subsequently withdrawn by her.
The food combining briefly described above is for efficient digestion
and Herbert Shelton's Food Combining Made Easy is available from
http://www2.anhs.org/anhs/ .
****************

[rebuttal]
*************
Time for a gastrointestinal physiology lesson.  The pH differs in
different parts of the gastrointestinal tract, no matter what you eat.
The normal pH in the stomach is highly acid.  Protein digestion does begin
in the stomach, but is completed in the neutral/alkaline environment of
the small intestine.  The trypsin, chymotrypsin, and other protein
digesting enzymes in the small intestine work best at a neutral pH.  The
pancreas secretes bicarbonate into the small intestine to neutralize the
acidity of the digesta coming from the stomach.  Not only is that to
improve the digestion of fat, carbohydrates, and protein, it's a
protective mechanism against ulceration of the small intestine.

Given the above, the "scientific" principle of food combining is on shaky
ground.
*************

[rebuttal to (1) see above]
***************
What? Your premise seems a bit screwy. The stomach is an acid
environment. Digestion begins with saliva, continues with the HCl in
the stomach. Next, the mass of glop (sorry for use of hi-tech medical
terminology) goes to the duodenum, first stop in the small intestine.
Guess what? That thar bile is pretty darn basic. The pancreas then
secretes different enzymes designed to chop the macronutrients up and
t he glop moves on. This sequence occurs no matter what you eat. (2)

Now, if the pancreas actually secretes relative amounts of lipase,
amylases and proteolytic enzymes at levels based on the content of the
duodenum, then maybe there'd be some kind of *beginning* rationale.
But that would be only if this differential secretion had some
salutory effect on pancreatic function. What studies are there to
suggest any of this is the case? (3)

So I think food combining is based on a fauty premise? Not that I eat
it very often, but honey, I do love steak and potatoes sometimes (my
sincere apologies to the cow).
****************

[rebuttal to (2)]
***************
ALL enzymes inevitably have limited pH ranges in which they operate.  If
the pH
gets above or below that range the enzyme will become orders of
magnitude less effective (making it for most purposes useless
(especially in a *limited exposure time* environment like the intestinal
system. (This is inherant in the fundamental chemcial makeup of enzymes
(which are proteins) and is true of ALL enzymes (as far as is known))
And, as was pointed out, it is impossible for the same part of the
gastrointestinal tract to have different pH's at the same time.
***************

[rebuttal to (3)]
*************
If the foods have widely differnt pH's then either they must have their
different pH's adjusted to within the same range or they must be exposed
to different pH's AND different enzymes *at different places* in the
intestinal tract.   Unless you have evidence that this occurs for ALL
ranges of pH's occurring in foods, the idea of seperating the ingestion
of certain foods makes sense.  (Testing it would be a good idea.  OFTEN
what "makes sense" does not conform to all-too-independant-minded
reality.)

It should also be noted, that, if the theory (as I understand it) is
right, the result would be that SOME of the foods eaten inappropriately
together would not be digested (at least by US - there might well be
bacteria that could handle it at the current pH.  Hmmm,  maybe that's
part of the reason why we have so MANY digestive problems).
*************

Walter.