CLASSIFICATION OF FOODs
This chapter is, I think, the only
one, which may seem a little complicated to take in and assimilate. Bear with
me if it seems rather technical; the remainder of the book, I promise you, will
prove very easy to read.
Throughout the rest of the book,
though, I shall be mentioning different categories of foods. If you are not
familiar with these categories, you will find the Method in general hard to
understand.
I have tried to reduce this chapter
to its simplest, including only the information that is essential to understand
what follows.
But if, despite this, you catch
yourself yawning over it and are feeling drowsy by line ten or so, skip to the
summary at the end of the chapter. Before you start actually trying to apply
the method, though, it will be essential to return to the main part of the
chapter, or you may not understand what you are doing.
Foods are edible substances
containing a number of organic elements, such as proteins, lipids,
carbohydrates, minerals and vitamins. They also contain water and non-digestible
matter, such as fibre.
PROTEINS
Proteins are the organic cells that
make up living matter: muscle, the various organs, including the liver and the
brain, the skeletal structure, and so on. They are themselves composed of
simpler elements called amino acids. The body manufactures some of these, while
most of the others are introduced into the body in a variety of foods. Food
protein comes from two sources:
—Animal sources: proteins are found
in large quantities in meat, fish, cheese, eggs, milk.
—Vegetable sources: soya, almonds,
hazelnuts, whole cereals and certain pulses also contain protein.
Ideally, we should consume as much
vegetable protein as animal. Protein is essential to the body:
—For building cells as a potential
source of energy, once it has been converted into glucose (via the Krebs
cycle).
—For making certain hormones and
neurotransmitters.
—For the production of nucleic acids
(essential for reproduction).
A diet deficient in protein can
have serious consequences for the body; these include muscle deterioration and
wrinkling of the skin.
A child should consume about 60g of
protein per day, while an adolescent needs 90g. The adult daily intake should
be 1g per kilogram of body weight, subject to a minimum of 55g for women and 70g
for men.
In addition, an adult's protein
consumption should represent at least 20 % of the daily energy intake. If
substantially too much protein is consumed, however, and physical activity is
low, the excess protein will remain in the body and is converted into uric
acid, which is the basic cause of gout.
With the exception of eggs, neither
animal proteins nor vegetable proteins alone can achieve the necessary balance
of amino acids.
The absence of one amino acid can
constitute an impediment to the assimilation of others. The diet should
therefore include both animal and vegetable proteins.
A vegan diet, based solely on
vegetable protein, will be unbalanced, in that it will be lacking in cystine,
which will result in problems with nail and hair growth. A vegetarian diet,
which includes eggs and dairy produce, on the other hand, can be perfectly well
balanced.
CARBOHYDRATES
Carbohydrates
are molecules composed of carbon, oxygen and hydrogen.
Blood glucose
level (glycaemia)
Glucose is the body's principal”fuel".
It is stored in the form of glycogen in the
muscles and liver. The blood glucose level (or blood sugar level, or glycaemia)
is simply the level of glucose in the bloodstream. On an empty stomach, this is
normally one gram per litre of blood.
When carbohydrates (bread, honey,
starchy foods, cereals, sweets, etc.) are ingested on an empty stomach, the
effect on the blood sugar level is found to be as follows :
The first stage is that blood
glucose rises (to a greater or lesser extent, according to the nature of the
carbohydrate).
The second stage is that, after
insulin has been secreted by the pancreas, the blood glucose level falls and
the glucose is released into the body's tissues.
So, thirdly, the blood sugar level
reverts to normal (see graph on the following page).
Traditionally, it was usual to
place carbohydrates in one of two distinct categories,”quick sugars”and”slow
sugars", the terms referring to the body's rate of absorbing them.
"Quick sugars”were simple
sugars (such as glucose) and disaccharides, such as the sucrose found in
refined sugars (both cane and beet), honey and fruit. The term”quick sugar”owed
its existence to the belief that, because of the simple nature of the molecule,
the body rapidly absorbed these sugars after ingestion.
Conversely,”slow sugars”referred to
all carbohydrates whose more complex molecule had first to be chemically
converted into simple sugar (glucose) in the course of digestion. This applied
notably to starches, from which, it was thought, glucose was released into the
body slowly and progressively.
This
way of classifying carbohydrates is today completely outdated, and is based on
a misconceived theory.
Recent studies show that the
complexity of the carbohydrate molecule does not actually determine the speed
with which glucose is released and absorbed into the body.
It is now accepted that the
glycaemic peak (that is, the point of maximum absorption) is reached at the
same rate for any carbohydrate eaten in isolation and on an empty stomach, and
occurs about half an hour after ingestion. Therefore, instead of talking about
their speed of absorption, it is more to the point to consider different
carbohydrates in terms of their potential to induce a greater or lesser rise in
blood glucose, that is, in terms of the sheer quantity of glucose they produce.
Disaccharides
(white sugar, maltose in beer, lactose in milk)
Polysaccharides
(cereals, flours, potatoes, pulses)
Monosaccharides
(glucose and fructose found in fruit and honey)
So scientists and others now agree in the
field of nutrition (see bibliography) that carbohydrates should be classified
according to what is called their hyperglycaemic potential, as defined by the
glycaemic index.
The glycaemic
index
The potential of each carbohydrate
to induce a rise in blood glucose (glycaemia) is defined by the glycaemic
index, first used in 1976. This index derives from the area below the curve
(shaded on the graph) of the hyperglycaemia induced by ingestion of the particular carbohydrate.
Glucose is arbitrarily given an
index of 100, standing for the area below its own hyperglycaemic curve. The
glycaemic index of other carbohydrates can then be arrived at using the
following formula:
The
greater the hyperglycaemia induced by the carbohydrate in question, the higher
will be its glycaemic index.
HIGH GLYCAEMIC INDEX
LOW GLYCAEMIC INDEX
It should be noted that chemical
processing of carbohydrates raises their glycaemic index. For example,
cornflakes have a glycaemic index of 85, while corn (maize) in its natural
state has an index of 70; instant potato has a glycaemic index of 95, whereas
the index of boiled potatoes is 70.
We also know that it is both the
quantity and the quality of the fibre in a carbohydrate which determines
whether it has a high or low index; soft white baps have an index of 95, white
baguette an index of 70, wholemeal bread 50, 100% stoneground wholemeal bread
35, white rice 70 and wholegrain rice 50.
Bad
Carbohydrates
These are all the carbohydrates whose
absorption leads to a large rise in blood glucose. This applies to table sugar
in whatever form (on its own or combined with other food stuffs, as in cakes).
The classification also covers all processed carbohydrates, such as white flour
and white rice, and also alcohol (particularly spirits), as well as potatoes
and corn (maize).
Good
Carbohydrates
Unlike the carbohydrates mentioned above,
“good carbohydrates” are those which are only partly absorbed by the body, and
which therefore produce a much smaller rise in blood glucose level. They
include whole cereals (unrefined flour, for example), wholegrain rice and some
starchy foods, such as lentils and broad beans. Most importantly, they also
include most fruits, and all the vegetables which are classified as fibre
(leeks, turnips, lettuce, green beans, etc.) and which all contain a small
quantity of glucose.
LIPIDS (or
FATS)
Lipids,
or fats, have complex molecules. They are divided into two broad categories,
according to their origin:
— Lipids of animal origin : these are
found in meats, fish, butter, cheese, cream, etc.
— Lipids of vegetable origin: these
include peanut oil, margarine, etc.
— Lipids can also be divided into two
categories of fatty acids :
— Saturated fatty acids,
found in meat, cooked meats and pates, eggs and dairy products (milk, butter,
cheese, cream).
—
Monounsaturated
and polyunsaturated fatty acids; these are the fats that remain liquid at room
temperature (sunflower oil, rapeseed oil, olive oil), though some can be
solidified by hydrogenation (as in margarine manufacture). Also included in
this category are all fish oils.
Lipids are necessary in the diet.
They contain a number of vitamins (A,D,E,K), as well as essential fatty acids
(linoleic acid and linolenic acid), and are needed for the synthesis of various
hormones. Only cold pressed virgin oils can be guaranteed to retain their
essential fatty acids.
When lipids are mixed with bad
carbohydrates, their absorption by the body is interfered with and, as a
result, a high proportion of the energy the lipids provide is stored as body
fat.
As a general rule, we eat too much
fat. Fried foods, doughnuts, unnecessary sauces and the use of too much fat in
cooking have crept into our eating habits; a lighter diet, avoiding excessive
use of fats, need be no less delicious.
Some of the lipids are the villains
in the cholesterol story, but here again, there are two types of
cholesterol,”good”and”bad". The aim should be to keep the total
cholesterol level as low as possible, with “good” cholesterol accounting for as
much as possible of the total. What
needs to be understood is that not all lipids lead to an increase
in”bad”cholesterol. In fact, some of them even tend to lower
the"bad”cholesterol level significantly. To give a complete picture, it is
necessary to divide fats into three further categories :
Fats which raise cholesterol These
are the saturated fats found in meat, butter, cooked meats, cheese, lard and
milk products.
Fats which have very little effect
on cholesterol These are the ones found in shellfish, eggs and skinless poultry.
Fats which lower cholesterol
These are the vegetable oils :
olive oil, rapeseed oil, sunflower oil, corn oil, etc.
As for fish oils, they play no real
part in cholesterol metabolism, but help prevent cardiovascular disease by
bringing down the level of triglycerides and helping avoid thromboses. We ought
therefore to consume oily fish (salmon, tuna, mackerel, herrings, sardines).
The weight-loss Method that I am suggesting depends in part on choosing between
“good” and “bad” carbohydrates. In the same way, choices have to be made
between “good” and “bad” lipids,
especially if you tend to have a high cholesterol level or simply want to
protect yourself permanently from the risk of it, with a view to avoiding
cardiovascular disease. Avoiding excessive consumption of saturated fats is an
essential part of the Method.
DIETARY FIBRE
Dietary fibre is a substance found
mainly in vegetables, pulses, fruit and whole cereals.
Although it is true that it has no
actual energy value, it nevertheless plays an extremely important role in the
digestive process. The cellulose, lignin, pectin and gums that it contains
ensure good intestinal function, and lack of dietary fibre is the cause of most
cases of constipation. Moreover, fibre is very rich in vitamins, major minerals
and trace elements,
without which serious deficiencies can occur.
It also blocks the absorption of
fats, so reducing the risk of atherosclerosis.
Fibre has yet another advantage. It
limits the toxic effects of certain chemical substances, such as additives and
colourings. And gastro-enterologists believe that some forms of fibre have the
property of protecting the colon from a number of risks, particularly that of
cancer.
Over recent decades, the rise in
the standard of living seen in industrialised countries has brought with it a
reduction in the amout of fibre consumed.
In France, for example, the current
average daily consumption of fibre is 20g, whereas the recommended daily intake
is 40g. In 1925, consumption of pulses, which are particularly rich in fibre,
was running at 7.3kg per person per year. Now it is down to 1.3kg. In Italy the
staple diet has always been pasta. But 30 years ago, the major part of
Italians' diet consisted of vegetables (high in fibre) and wholewheat pasta
that is, pasta made with whole flour containing the wheat fibres .
SOURCES OF FIBRE with fibre content per 100 g of
food
Cereal Products
|
Dried Vegetables
|
Oily dried fuit
|
||||||
Bran
Wholemeal Bread
Wholemeal Flour
Wholegrain Rice
White Rice
White Bread
|
40g
13g
9g
5g
1g
1g
|
Dried Beans
Split peas
Lentils
Chickpeas
|
25g
23g
12g
2g
|
Dessicated coconut
Dried figs
Almonds
Raisins
Dates
Peanuts
|
24g
18g
14g
7g
9g
8g
|
|||
Green Vegetables
|
Fresh Fruit
|
|||||||
Cooked peas
Parsley
Cooked spinach
Lamb’s lettuce
Artichokes
Leeks
|
12g
9g
7g
5g
4g
4g
|
Cabbage
Radishes
Mushrooms
Carrots
Lettuce
|
4g
3g
2.5g
2g
2g
|
Raspberries
Pears with skin
Apples with skin
Peaches
|
8g
3g
3g
2g
2g
|
|||
With today's higher standard of
living, meat has more often than not replaced vegetables, while pasta is
manufactured with refined, white flour, from which the fibre has been removed.
This is the explanation given by Italian doctors for a higher incidence of
obesity and also for the alarming increase in cancers of the digestive tract.
Furthermore, it has been shown that
fibre has a beneficial effect on obesity. Introducing it into the diet has the
effect of reducing both the blood glucose level and the level of insulin in the
blood; as we shall see in the following chapter, it is these two factors that
are responsible for the laying down of body fat.
Of the four main groups of
nutrients, proteins are absolutely essential to our bodies, as they contain
vital amino acids which we cannot make ourselves. Equally important are certain
lipids, which contain vitamins and essential fatty acids (linoleic acid and
linolenic acid) that our cells are incapable of producing independently. Only
carbohydrates can be considered more expendable, since the human body is able
to make its own glucose from stored fat.
It has to be understood, though,
that lipids and proteins are often found in combination in the same foods; meat
is an example.
On the other hand, only
carbohydrates and lipids have high energy potential. That is why, for
simplicity's sake, we will largely ignore the question of protein.
So whenever we mention a particular
food, we will simply put it in one of the following three categories:
—
carbohydrates (specifying whether
they are ”good” or ”bad")
—
lipids
—
dietary fibre
When a food contains both
carbohydrate and lipids, as in the case of peanuts, we will refer to it as a
carbohydrate-lipid .
SUMMARY
Proteins are substances
contained in a number of foods of animal or vegetable origin. They are found in
meat, fish, eggs, diary produce and pulses. Proteins are indispensable
to the human body and do not make us fat. Carbohydrates are substances
that are metabolised into glucose. They occur in foods which originally contain
either sugar (fruit, honey) or starch (flour, cereals, starchy foods) All
carbohydrates ingested on an empty stomach are absorbed at the same rate. They
are classified according to their potential for raising blood glucose; this
potential is measured by the glycaemic index. It is therefore possible to draw
a distinction between ”good” and ”bad carbohydrates” with a high index. Lipids
are substances that may be of either animal or vegetable origin. They are fats
(meats, cooked meats, fish, butter, oil, cheeses etc...) Some have the potential
to raise blood cholesterol (meat, dairy products) while others actually help to
lower it (olive oil etc ) Dietary fibre : in this category come all
green vegetables (lettuce, chicory, leeks, spinach, French beans, etc) Some
dried vegetables, fruit and whole grains also contain a significant amount of
fibre. It should be consumed frequently; failure to do so can lead to serious
deficiencies.
LIST OF FOODS CLASSIFIED AS LIPIDS,
CARBOHYDRATES,
CARBOHYDRATE-LIPIDS
OR DIETARY FIBRE
(1)
All the foodstuffs in this column (except butter, oils and
margarine) contain protein.
(2)
Some carbohydrate foods, such as pulses, also contain protein.
(3)
Containing a very small amount of carbohydrate .
LIPIDS
(1)
|
CARBOHYDRATES
(2)
|
CARBOHYDRATE-LIPIDS
|
DIETRY
FIBRE (3)
|
MEATS
|
FLOUR
|
UNSKIMMED
MILK
|
ASPARAGUS
|
-
LAMB
|
BREAD
|
WALNUTS
|
GREEN
SALADS
|
-
BEEF
|
RUSKS
|
HAZELNUTS
|
SPINACH
|
-
VENISON
|
POTATOES
|
ALMONDS
|
TOMATOES
|
-
VEAL
|
RICE
|
PEANUTS
|
AUBERGINES
|
-
PORK
|
PASTA
|
BRAINS
|
COURGETTES
|
COOKED
MEATS
|
SEMOLINA
|
LIVER
|
CELERY
|
POULTRY
|
TAPIOCA
|
SOYA
FLOUR
|
CABBAGE
|
RABBIT
|
DRIED
BEANS
|
WHEATGERM
|
CAULIFLOWER
|
FISH
|
PEAS
|
EGG
PAST
|
SAUERKRAUT
|
CRAB
|
LENTILS
|
CASHEWS
|
FRENCH
BEANS
|
SHRIMPS
|
CHICKPEAS
|
COCONUT
|
LEEKS
|
SCAMPI
|
CARROTS
|
CHOCOLATE
|
ARTICHOKES
|
LOBSTER
|
SUGAR
|
OLIVES
|
PEPPERS
|
EGGS
|
HONEY
|
CHESTNUTS
|
CHICORY
|
BUTTER
|
MAOZE
|
SWEET
CHESTNUTS
|
MUSHROOMS
|
CHEESES
|
FRUIT
|
SCALLOPS
|
TURNIPS
|
OILS
|
DRIED
FRUIT
|
OYSTERS
|
SALFISH
|
MARGARINES
|
AVACADO
|
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