POPULAR DIETS
Part Three: 'Other Diets'
(Neither High Carbohydrate nor High Protein Diets)
SUMMARY
For the full
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A lot of publicity has been given to a wide variety of
diets lately. Some of these advocate high protein intake, some stress
carbohydrate, while others make no reference to carbohydrate or protein. What
are these diets supposed to achieve, and what, if any, is the scientific
evidence supporting them?
This answer is brought to you by many of the Australian
nutrition professionals who regularly contribute to a nutrition email discussion
group.
Over the past several years many diets have been
recommended to the public, often with promises of improved health, greater life
expectancy, and/or weight loss resulting from adoption of each particular diet.
Most of these diets can be assigned to the 'high protein' or 'high carbohydrate'
category, although some don't fit neatly into either category.
The first point that needs to be made is that the term
'diet' doesn't have the meaning it may have had a few years ago--that is, a
short-term change in eating patterns to attain a specific goal (such as losing
weight). Now, the proponent of a diet is usually advocating an eating plan for a
lifetime, not a short-term means of overcoming a perceived problem (such as
being overweight).
In this summary answer (Popular Diets: Part 3), some
popular diets that are not clearly high-protein or high-carbohydrate are
reviewed. Several high-protein diets are reviewed in Part 1, while popular
high-carbohydrate diets are the subject of Part 2 of this FAQ.
The diets reviewed below are 'Potatoes Not Prozac'; the
'New Beverley Hills Diet'; 'Eat Right for Your Type'; 'Fit for Life' and the
Liver Cleansing Diet. These diets are reviewed in no particular order.
POTATOES NOT PROZAC
This diet is based on the belief that many people have an 'undiagnosed sugar
intolerance'. The author believes that you can improve your physical and mental
health by following several simple steps. These include establishing a food
intake diary and using this diary to identify inappropriate food habits; eating
three meals a day at regular intervals; adjusting carbohydrate intake to include
more complex carbohydrate foods; and creating a plan to maintain your revised
food habits. These are all sensible suggestions, but, unfortunately, the
suggestions do not stop there. Also recommended are: taking vitamin supplements;
eating a recommended amount of protein at each meal; and reducing (or
eliminating) intake of sugars.
Taking vitamin supplements, except when prescribed by a
doctor or dietitian, is considered inappropriate (and potentially dangerous) by
most orthodox nutritionists. The two remaining suggestions (a specified level of
protein at each meal and avoiding eating sugars) are relatively harmless, but
unnecessary for sound nutrition.
In summary, despite having some good points, Potatoes Not
Prozac cannot be recommended as a sound eating plan in either the short or long
term.
THE NEW BEVERLEY HILLS DIET
The New Beverley Hills Diet is based on the belief that the enzymes needed
by the body to break down particular foods are found in those foods. For
example, fruits are supposed to contain the enzymes needed by the body to allow
those fruits to be broken down.
This is incorrect: it is the body--not the food we
eat--that produces the digestive enzymes we need to break food down. Based on
another major misunderstanding of nutritional science, the conclusion is drawn
by the author of this diet that having undigested food in the intestine leads to
increase in body fat. This is also incorrect: only digested food can lead to
body fat accumulation. To counter the (claimed) problem of having undigested
food in the intestine, the author advises eating a single food, and nothing but
that food, for an entire day. This is inappropriate: people must eat a wide
variety of foods to obtain the nutrients needed for optimal health.
In conclusion, the New Beverley Hills Diet cannot be
recommended for either short periods (eg, during weight loss) or as the lifelong
diet.
EAT RIGHT FOR YOUR TYPE
Based on the concept that our blood types evolved at different stages in the
evolution of humans, this diet advocates eating specific diets--and taking part
in particular activity patterns--based on blood type.
Although there is evidence supporting different diets at
different stages of development of human populations, there is no evidence to
support the proposition that our blood types evolved as a result of the adoption
of different eating patterns.
The recommendations given in this diet have no scientific
basis whatsoever. Most Australians have the enzymes needed to digest a wide
range of foods, and any food intolerances that do exist (such as an inability of
some adults to digest large quantities of milk) are unrelated to blood type.
The Eat Right For Your Type diet has no basis in science
and no aspect of this diet can be recommended.
FIT FOR LIFE
The main basis of Fit For Life is the belief that eating when you are ill,
or combining protein and carbohydrate foods at the one meal when you are well,
leads to the accumulation of undigested food in the intestine. This food will,
according to the author of this diet 'putrefy' (that is, rot) in the intestine.
Examples of food combinations that will (it is claimed) lead to this problem
include eating bread with cheese, meat with potatoes, and eggs with toast.
There is no scientific evidence to support this idea. The
human body is superbly adapted to digest a wide range of foods, eaten either
individually or in combination with other foods.
The authors go further and claim that the putrefaction of
the undigested food (which they believe results from food combining) can
actually lead to obesity. In fact, it is only digested food that can contribute
to kilojoule intake and lead to accumulation of body fat.
In summary, Fit For Life is based on a complete
misunderstanding of the basic principles of nutrition. It cannot be recommended
for use in either the short or the long term.
THE LIVER CLEANSING DIET
This diet is based on the premise that much of the illness seen in today's busy
and polluted world is caused by 'liver dysfunction'. The claim is made that by
following this diet, your liver will be 'cleansed' and you will experience:
'increased energy levels; detoxification and cleansing of the blood stream;
reduction of inflammation and degenerative diseases; better immune function;
more efficient fat metabolism and weight control.'
Although the basis of this diet is rather unorthodox, much
of the dietary advice is quite sound. Emphasis is placed on reducing saturated
fat intake, increasing fibre intake, eating a wide variety of nutritious foods
and moderating consumption of sugars.
Unfortunately, the advice also includes recommendations to
eat only raw fruits and vegetables, many nutritional supplements and to take
'liver tonics'. There is little or no scientific evidence supporting the value
of this advice. In fact, many vegetables are very difficult to digest in the raw
state and there is doubt about the safety of some nutritional supplements. The
value of 'liver tonics' has yet to be demonstrated scientifically. Dr Cabot also
neglects to stress the importance of physical activity in promoting and
maintaining health and wellness.
Although the Liver Cleansing Diet contains some valuable
dietary advice, it is not based on sound science and cannot be recommended for
either the short or long term.
See the other Popular Diet Frequently Asked Questions in
this series:
Part One:
High Protein Diets
Part
Two: High Carbohydrate Diets
For more information Nutrition Australia recommends:
Back
to Frequently Asked Questions Index
Disclaimer: This material is provided on the basis that it
constitutes advice of a general nature only. It is not intended to replace the
advice of a physician or a dietitian.
[Date issued: November 2000]
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