Robert Beck wrote:

>>Dr. Susanne Holt wrote that my health improvements may be due to other than
>>the elimination of grains & dairy products from my diet:......
>>To my best estimate, total fat and saturated fat probably remained fairly
>>constant.  Total caloric intake was lower.  Total fiber intake decreased
>>markedly, (along with digestive & bowel problems (heartburn, gas, bleeding,
>>general discomfort)). Rapidly-digested CHO was eliminated, while sodium may
>>have increased due to large amounts of meat ingested   (I use KCl instead
>>of NaCl at table).  CHO in my diet came largely from green & leafy
>>vegetables and, sparingly, from fruits
>>Exercise was not so much increased as shifted from entirely aerobic to a
>>mix of strength and aerobic training.

I would like to stress again - that the health improvements Robert Beck has
experienced are due to the combination of changes he has made to his diet
and lifestyle, and Robert seems to be agreeing with this conclusion at the
end of his last email.  It would be beneficial to conduct a controlled
cross-over study using a group of healthy lean subjects, a group of healthy
overweight subjects, and a group of subjects with symptoms of insulin
resistance consume each of the 3 following diets for a period of several
months, in random order:
1. a diet that includes refined cereal products;
2. a diet that contains less refined/wholegrain cereal products; and
3. a diet that completely eliminates cereal products.

This kind of study would provide some more objective evidence to either
confirm  the hypothesis that all grain products result in undesirable
physiological responses in all people.
Obviously, it would be good to keep the macronutrient and total energy
contents of these 3 diets the same, but this could be a bit of a challenge.
Furthermore, it would be beneficial to ensure that the people within each
subject group commenced the study at a similar physiological state and
nutritional status.   Ideally, this kind of study would be done in a
metabolic ward setting.

Robert also wrote: <<If people of the caliber of Drs Cordain, Brand-Miller
and Holt could be persuaded to develop the protocols, there are probably
enough interested,motivated people among the participants....to serve as
record-keepers and other functionaries in a controlled, well-planned test of
the concepts of paleo-diets>>
We are certainly motivated enough to carry out these kind of studies, and
indeed continue to submit such protocols to various scientific bodies in
control of awarding research grants. Unfortunately, nutrition-related
research often does not have a high priority rating, so it is incredibly
difficult to get enough money to perform these large controlled dietary trials.


Dean Esmay wrote:
<<Regarding the claim that "not all cereal grains are necessarily unhealthy"
-- can Dr. Holt elaborate on which ones she feels are not unhealthy, and
what criteria she uses to reach this conclusion?>>
The long-term consumption of diets which induce relatively high blood
glucose and insulin responses after eating, (ie based on highly-refined
cereal products) appear to be associated with the development of insulin
resistance and other related health problems (refs 1-3). Less refined cereal
products produce lower but more sustained elevations in blood glucose levels
and are also more difficult to eat and more satisfying (eg ref 4).
Again, health problems are likely to be due to a combination of dietary,
lifestyle and genetic factors.
Not all grain eaters suffer from heart disease, overweight etc.

However, a very very high-Carb diet that does not have much fat or protein
could be unhealthy, particularly if people are avoiding whole food groups
like meats and dairy products.

Dean Esmay also wrote: <<Regarding the claim that health benefits of
substantial weight loss,decreased triglycerides, and increased
HDLcholesterol could be ascribed to a low-fat diet--what is this based on?
Every study I have seen on low-fat diets among westerners has shown a trend
toward decreased HDL cholesterol.  Increases in triglycerides are also a
common result.  Furthermore, after more than a year of reviewing research
on low-fat diets, I have found not one study which boasts more than very
small weight loss benefits, usually on the order of a kilogram or two,
awong obese subjects--and some studies show substantial weight gain in some
subjects using such diets.  Lowered fat and lowered caloric intake over the
last decade in the United States have correlated with record increases in
obesity and diabetes.

I did not ever make a claim that low-fat, high-carb diets are effective in
producing weight loss in obese people.  This was not an issue I introduced.
Re: the effects of diet on weight loss, it is essential to consider the
group of subjects being studied and how the dietary information was collected.
For example, many of the obese subjects in dietary trials are the hard-core
difficult cases in hospital clinics with a very long history of failed
diets.  Do you really expect to see substantial weight loss maintained over
time?
There is also quite a bit of evidence now to confirm that obese people tend
to underreport their actual food intake in diet diaries/food frequency
questionnaires etc.
Low-fat, high-carb diets have been shown to be useful in preventing weight
gain in some studies (if the total amount of energy is decreased) and have
resulted in the loss of a few kilos in normal weight subjects (who didn't
need to lose weight anyway).  It is important to consider the types of foods
used in the studies, since a high-carb diet based on relatively energy-dense
high-carb foods (white bread, honey, fruit juice, mashed potato, lentil
dhal) will facilitate a greater energy intake than less energy-dense carb
foods which contain less energy per gram and usually more intact fibre
(wholegrain bread, whole fruit, boiled unpeeled potato, boiled whole
lentils) (see review ref 5).
Perhaps the energy density of the average USA diet has increased (ie
calories per gram food eaten) while energy expenditure has decreased?  Quite
a few of the low- to zero-fat processed foods available in the USA have had
the fat replaced with dense carbohydrates - so they don't really contain any
less calories.

Sucessful weight loss requires the individual to make dietary and lifestyle
changes that they can maintain in order to consume fewer calories than they
are expending.  It is a very individual thing.  Some people lose weight by
skipping breakfast, most people don't, etc etc.
An excellent book which describes the individual changes made by people who
have successfully lost weight and maintained this loss is called
"Thin for life - 10 keys to success from people who have lost weight and
kept it off" by Anne M Fletcher, published by Chapters publishers and
booksellers, 2085 Shelburne RD, Shelburne VT 05482, USA.

Dean Esmay also wrote re:<<the claim that excess protein is oxidized by the
body as fuel,"which pushes both carb and fat into starage", can Dr. Holt
elaborate?  Is she suggesting that in two diets of, say, 2000 kCals daily,
one of 15% protein and the other of 30% protein, the latter will cause
faster storage
of fat than the former?  >>>

There is a growing body of metabolic research which confirms that there
appears to be a hierarchy (protein > CHO > fat) in the extent to which the
stores of the macronutrients are autoregulated by oxidation. An excess carb
intake tends to promote fat storage (but not de novo fat synthesis) (See ref
6).  Fat storage will also be influenced by: total fat intake; total energy
intake vs total energy expenditure; and possibly by the type of proteins and
carbs ingested.

References

1. Slabber et al (1994)Effects of low-insulin response, energy-restricted
diet on weight loss and plasma insulin concentrations in hypoerinsulinemic
obese females. Am J Clin Nutr 60:48-53.

2. Salmeron et al (1997)  Dietary fiber, glycemic load, and risk of NIDDM in
men.  Diabetes Care 20: 545-50.

3. Salmeron et al (1997) Dietayr fiber, glycemic load and risk of NIDDM in
women.  J Am Med Assoc (JAMA) 12: 472-77.

4. Holt & Brand Miller (1994) Particle size, satiety and the glycaemic
response.  Eur J Clin Nutr 48: 496-502.

5.  Poppitt and Prentice (1996) Review on energy density and energy intake.
Appetite.
Dr Susanne Holt
CSIRO - Division of Human Nutrition
PO Box 52
NORTH RYDE
NSW 2113
AUSTRALIA

Ph (+61) 02 9490 8425
Fax (+61) 02 9887 8511
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