I’m responding to Jim’s post on the list for several reasons: 
1.	I think it is an important issue here; 
2.	I believe that Jim will accept my comments in a spirit of friendly
debate and discourse;
3.	I believed similarly until I was working more extensively with
weight loss clients.  My experience there has led me to some different
beliefs, all of which still fit into the Paleo perspective.

While high fat and low carb is ideal for me, some family members, and many
friends and acquaintances, it is not ideal, or even good, for some of the
people I have worked with. When fats are either not absorbed or not
metabolized normally, a host of health problems can arise. These range from
those that are easy to spot from the characteristic fat deposits in unusual
and very visible places in the body such as in the eyelids, on the forehead,
etc. to those that are only seen internally, where fats are deposited on
vital organs such as the heart, liver, etc. These include four or five
coenzyme A dehydrogenase deficiencies, one carnitine transporter deficiency,
several carnitine enzyme deficiency disorders, some mitochondrial protein
deficiencies, fatty acid enzyme deficiencies, and a number of lipid
metabolism diseases. These latter include Fabry disease, Farber’s disease,
Krabbé disease, metachromatic leukodystrophy. cholesteryl ester storage
disease, Wolman disease, Gaucher disease, Niemann-Pick disease, and there is
some evidence to implicate  adreoleukodystrophy as a disease that involves
disturbances of fat metabolism. 

I think that people with these and similar conditions, who want to lose
weight, should be encouraged to follow a low fat diet. Another factor that
should be taken into account is whether there is insulin resistance. Those
who wish to lose weight but do not have insulin resistance may fare better
reducing their total caloric intake instead of high fat and low carb. Other
factors that may be important to consider include base metabolic rates and
daily activity levels. For instance, endurance runners, in the absence any
of the above conditions that involve lipid metabolism errors, would do well
to follow a low carb, high fat diet for at least 45 days before they begin
training. Sprinters, on the other hand, might be better served by a diet
that involves more conventional ratios of carbohydrates, proteins, and
lipids, although I haven’t been able to find any data relevant to sprinters.


In general, while I agree with Jim’s assertion that a majority of humans
will fare better on a diet low in carbohydrates and high in fats, I think it
is important to recognize the minority whose health may not be well served
by such diets. 

Relatedly, the most frequent objection I hear about the ketogenic diet is
that people feel sick and nauseated. Some even report vomiting. I suspect
that they are approaching ketoacidosis. It is usually a very effective
antidote to just have them eat a small quantity of sugar, then reduce their
protein intake and increase their fat intake. The sugar will reverse most
symptoms in about 15 minutes, if the person does not have diabetes.    

My journey down this Paleolithic rabbit hole keeps teaching me to try to be
flexible in what I say. My son once gave me a plaque that says “Lord help me
to keep my words kind and gentle today because tomorrow I may have to eat
them.” :-)
Best Wishes, 
Ron