Principles of nutrition and dietetics; nutritional disorders and their treatment

1. Nutrition and Diet
R. C. Gupta
M.D. (Biochemistry)
Jaipur (Rajasthan), India

2. We require energy for various biological
activities
The energy is provided by food
The daily food intake should be sufficient to
meet the energy requirement

3. The conventional unit of energy is calorie
One calorie (cal or small calorie) is the
thermal energy required to raise the
temperature of 1 gm of water by 1°C

4. In human physiology, energy is generally
expressed in kilocalories
Kilocalorie is also known as kcal or large
calorie or Calorie
One kcal is equal to 1,000 cal

5. In the international system of units, unit of
energy has now been changed to joule (J)
One joule is the energy required to move
a mass of one kg by one metre distance
by a force of one newton

6. One calorie equals 4.184 (≈ 4.2) joules
Hence, 1 kcal = 4.2 kJ
1,000 kcal = 4.2 MJ (megajoule)
240 kcal = 1.0 MJ
However, kcal is still widely used as a unit
of energy

7. The energy-yielding nutrients (proximate
principles of food) are carbohydrates, lipids
and proteins
Energy given by carbohydrates, lipids and
proteins can be measured by a bomb
calorimeter
Calorific value of foods

8. A weighed amount of the substance is
burned in bomb calorimeter by an
electrically heated platinum wire in the
presence of oxygen
The heat evolved is absorbed by a fixed
quantity of water which surrounds the
burning chamber

9. The rise in temperature of water is
measured by a thermometer
The heat evolved by complete burning of
one gm of the substance is calculated, and
is known as its calorific value

11. Calorific values of different nutrients
determined by bomb calorimetry
Class of nutrient Calorific value
Carbohydrates 4.1 kcal/gm
Lipids 9.3 kcal/gm
Proteins 5.4 kcal/gm

12. When carbohydrates, lipids and proteins
are oxidized in the body, their calorific
values are different
Carbohydrates and lipids liberate slightly
less energy in the body
Their digestion and absorption is not
100%

13. A major difference is seen in case of
proteins
In a bomb calorimeter, the proteins are
completely oxidized
In human beings, the end-product of
protein catabolism is urea

14. Urea is capable of giving some energy
However, human beings cannot utilize
urea
Therefore, the calorific value of proteins
in the body is significantly less

15. Calorific values of different nutrients in
the body are:
Nutrient Calorific value
Carbohydrates 4.0 kcal/gm
Lipids 9.0 kcal/gm
Proteins 4.0 kcal/gm
Alcohol (ethanol) is another energy-
rich compound with a calorific value of
7 kcal/gm

16. Energy expenditure of a person
The energy actually spent by a living
person can be measured by:
Direct
calorimetry
Indirect
calorimetry

17. The subject is kept in an insulated
chamber surrounded by water
The rise in temperature of water is
measured over a fixed period
From this, the energy produced per hour
or per minute can be calculated
Direct calorimetry

18. Direct calorimetry
Heat Heat
Water
out
Insulation
Water
in
Fresh air
Exhaled air
Oxygen
consumption

19. Volume of O2 inhaled and CO2 exhaled by
a person is measured over a fixed period
From this, the energy produced by the
person is calculated
Energy production is calculated from the
respiratory quotient (RQ)
Indirect calorimetry

20. RQ is the ratio of the volume of CO2
produced and O2 consumed
RQ depends upon diet
RQ of carbohydrates, lipids and proteins
is different

21. RQ of carbohydrates is nearly one
For example, oxidation of one glucose
molecule uses six molecules of O2 and
produces six molecules of CO2
RQ of carbohydrates
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O
RQ = 6/6 = 1

22. Lipids molecules have less oxygen in
them than carbohydrates
Therefore, they require more oxygen for
their oxidation
For example, oxidation of one molecule
of stearic acid uses 26 molecules of O2,
and produces 18 molecules of CO2
RQ of lipids

23. C17H35COOH + 26 O2 → 18 CO2 + 18 H2O
RQ = 18/26 = 0.7
Stearic acid

24. Amino acid composition of each protein is
unique
Molecular formulae of different amino
acids are different
Hence, different proteins differ in their RQ
The average RQ of proteins is about 0.8
RQ of proteins

25. RQ of a mixed diet is about 0.85
At this RQ, 1 litre of O2 used represents
energy production of 4.825 kcal
So, energy spent by a person in a given
period can be calculated from:
Volume of O2 inspired
Volume of CO2 expired

26. Indirect calorimetry

27. Energy requirement of an individual is
equal to his energy expenditure
Ideally, the energy requirement should
be calculated from the energy
expenditure of individuals
But this is not practicable
Energy requirement

28. Energy requirement has to be recomm-
ended for a whole community
Factors to be considered while
calculating energy requirement are:
Basal metabolic rate
Specific dynamic action of food
Physical activity
Provision for growth

29. Basal metabolic rate (BMR) is the energy
spent by a subject in basal condition i.e.
complete physical and mental rest
BMR is expressed in kcal/hour/square
metre of body surface area
Basal metabolic rate

30. BMR is the energy spent for main-
taining vital activities
Vital activities are circulation, respira-
tion, peristalsis, maintenance of body
temperature etc
These activities don’t stop even when
one is at rest or asleep

31. Energy equal to 24-hour BMR is spent
daily to sustain the vital functions
A provision has to be made for BMR
while calculating energy requirement

32. The measurement is made after a 12-
hour period of rest and fasting
The subject should be recumbent but
awake during the measurement
The environmental temperature should
be comfortable and not above the body
temperature
Measurement of BMR

33. BMR is usually measured by Benedict-
Roth apparatus
The subject breathes comfortably into
the mouth-piece of the apparatus
O2 inhaled over a 6-minute period is
measured and corrected to NTP (normal
temperature and pressure)
This is multiplied by 10 to get the hourly
oxygen consumption

36. Assuming an RQ of 0.85, each litre of
O2 consumed represents an expenditure
of 4.825 kcal of energy
The energy spent per hour is divided by
the body surface area of the subject to
get the BMR

37. Body surface area can be calculated by:
• Du Bois formula, which is:
A = 0.007184 × H0.725 × W 0.425
where A is body surface area in square
metres, H is height in cm and W is
weight in kg
• Nomograms which directly relate the
height and weight of a subject with his
body surface area

39. The BMR is high in childhood and
gradually decreases until old age
The average BMR is:
40 kcal/hour/square metre
in adult men
36 kcal/hour/square metre
in adult women

40. BMR is affected by a number of
conditions
Physiologically, the BMR is higher in:
Males than in females
Younger persons than in older persons
Colder climate than in warmer climate
Non-vegetarians than in vegetarians

41. BMR is increased in:
Pregnancy
Hyperthyroidism
Fevers
Severe anaemia
Polycythaemia

42. BMR is decreased in:
Starvation
Hypothyroidism
Adrenal insufficiency

43. Intake of food increases energy produc-
tion in the body
This happens even in the basal state
This is due to specific dynamic action
(SDA) or thermogenic effect of food
Specific dynamic action

44. After taking food, some energy is spent
for digestion, absorption, transport, meta-
bolism and inter-conversion of nutrients
The energy thus spent is known as the
SDA of food
Proteins have the highest SDA

45. When 25 gm protein is ingested, about
30 kcal are spent in metabolizing it
The energy given by 25 gm of protein is
100 kcal but 30 kcal have to be spent to
gain this energy
So, the net gain of energy from 25 gm of
protein is 70 kcal only
Thus, the SDA of proteins is about 30%

46. SDA of lipids is about 13%
SDA of carbohydrates about 5%
When different foodstuffs are taken
together, the SDA is less than the sums
of SDA of individual foodstuffs

47. Carbohydrates and lipids lower the SDA
Lipids cause a greater lowering of SDA
than carbohydrates
A mixed diet containing proteins, lipids
and carbohydrates has an SDA of about
10%

48. If a mixed diet having 3,000 kcal is taken
in a day, 300 kcal would be spent on
account of SDA
The net energy gain would be 2,700 kcal
only
Therefore, an additional provision of
10% has to be made on account of SDA

49. Physical activity involves muscular work
The energy expenditure increases above
the basal level
Therefore, an extra provision has to be
made for physical activity
The increment depends upon the type of
physical activity and its duration
Physical activity

50. Some physical activities are common to
all
These include sitting, standing, walking
about etc
Energy expended in these activities is
similar in all persons of the same sex

51. Men, sitting at rest, spend about 100
kcal/hour
While standing, the energy expenditure
rises to about 110 kcal/hour
Women, sitting at rest, spend about 70
kcal/hour
During standing, the energy expenditure
of women goes up to 80 kcal/hour

52. Occupational work can be divided into 3
types depending upon the occupation:
Sedentary work
Moderate work
Heavy work
However, the energy expenditure differs
in different types of occupation work

56. Energy expenditure of men during
sedentary work is about 110 kcal/hour
Energy expenditure of men during
moderate work is about 150 kcal/hour
Energy expenditure of men during heavy
is about 280 kcal/hour

57. Energy expenditure of women during
sedentary work is about 90 kcal/hour
Energy expenditure of women during
moderate work is about 125 kcal/hour
Energy expenditure of women during
heavy work is about 210 kcal/hour

58. Type of
work
Men
(kcal/hour)
Women
(kcal/hour)
Sedentary
work 110 90
Moderate
work 150 125
Heavy
work 280 210
Energy expenditure during
occupational work

59. In growing age, an extra provision has
to be made for formation of tissues
An extra provision is also required in
pregnancy and lactation
Provision for growth

60. In pregnancy, an extra provision is
required for the growing foetus
An extra allowance has to be made
during lactation also
This should be equal to the energy value
of milk secreted by the nursing mother

61. Recommended energy intake
Energy requirement of an individual
can be calculated from his/her:
BMR
SDA
Type of occupation
The hours spent in sleep, at
rest and in occupational work
Growth requirements, if any

62. Requirements for Indians have been laid
down by Indian Council of Medical
Research (ICMR)
These requirements are for a reference
man or woman of the community
Necessary adjustments are to be made
for any deviation from the reference
standard

63. An Indian reference man is 20-39 years of
age and has a body weight of 60 kg
He is engaged in sedentary occupation
An Indian reference woman is 20-39 years
of age and has a body weight of 50 kg
She is engaged in sedentary occupation/
household work

64. The Indian reference man spends:
Eight hours in sleep
Eight hours in occupational work
Six hours sitting, reading, writing etc
Two hours in household work,
walking, recreational exercise etc

65. We can now calculate the
energy requirement of:
A reference man
A man engaged in moderate
occupational work
A man engaged in heavy
occupational work

69. The Indian reference woman spends:
Eight hours in sleep
Eight hours in sedentary work
Six hours sitting, reading, writing etc
Two hours in household work,
walking, recreational exercise etc

70. We can now calculate the
energy requirement of:
A reference woman
A woman engaged in
moderate occupational work
A woman engaged in heavy
occupational work

74. ICMR (1980) has recommended energy
allowances (safe energy intake) for Indian
males and females of different age groups
Infants (0 - 6 months) 120/kg of body weight
Infants (7-12 months) 100/kg of body weight
Children (1-3 yrs) 1200
Children (4-6 yrs) 1500
Children (7-9 yrs) 1800
Children (10-12 yrs) 2100

76. DIET
Energy is provided by food
The food consumed daily constitutes diet
However, provision of energy is not the
sole function of diet
The diet must meet the requirements of
all the nutrients

77. Proteins, lipids and carbohydrates are the
proximate principles of diet, and will be
discussed here
The roles of vitamins, minerals and water
will be discussed separately

78. Proteins
Proteins are required mainly for formation
of tissues
Even adults require proteins for
replacement of worn out tissues
When proteins are taken in excess, they
can be used as a source of energy also

79. If energy is not available from carbo-
hydrates and lipids, tissue proteins are
broken down to provide energy
While considering the nutritional role of
proteins, we have to take into account their
quality as well as quantity

80. All the dietary proteins are not of the
same nutritional quality
Some proteins are nutritionally superior
as compared to others
Quality of proteins

81. The nutritional quality of proteins
can be assessed on the basis of:
Essential amino acid content
Digestibility coefficient (DC)
Biological value (BV)
Net protein utilization (NPU)
Protein efficiency ratio (PER)

82. Eight amino acids are considered to be
essential for human beings as these are
not synthesized in the human body
These are valine, leucine, isoleucine,
threonine, methionine, lysine, phenyl-
alanine and tryptophan
Essential amino acid content

83. Two amino acids - arginine and histidine -
are considered to be semi-essential
Their endogenous synthesis doesn’t
suffice in infancy and childhood
The other amino acids are synthesized in
the body in adequate quantities

84. Cysteine can partially meet the require-
ment of methionine
Similarly, tyrosine can partially meet
the requirement of phenylalanine

85. A good protein should provide all the
essential amino acids
Deficiency of even a single amino acid
can impair the synthesis of proteins
Animal proteins contain all the essential
amino acids
Vegetable proteins are usually deficient
in one or more essential amino acids

86. The essential amino acid, deficient in a
protein, is known as its limiting amino acid
Lysine and threonine are the limiting
amino acids in cereals
Methionine is the limiting amino acid in
pulses

87. Groundnut is poor in lysine, threonine
and methionine
Maize is poor in lysine, methionine and
tryptophan
Soya bean is deficient in methionine
Thus, animal proteins are superior to
vegetable proteins in terms of essential
amino acid content

88. Like carbohydrates and lipids, proteins
are digested in the gastrointestinal tract,
and are then absorbed
The percentage of ingested protein
absorbed from a foodstuff is known as
its digestibility coefficient
Digestibility coefficient (DC)

89. The percentage of dietary protein (or
nitrogen) retained in the body after its
digestion and absorption is known as its BV
Different foods differ in their BV
Biological value (BV)

90. NPU is a measure of utilization of dietary
proteins for protein synthesis in the body
It depends upon the digestibility and
biological value of a foodstuff
Net protein utilization (NPU)
Nitrogen ingested
Nitrogen retained
NPU = x 100

91. Proteins are used mainly for formation of
tissues
PER is the gain in body weight (gm) per
gm of protein ingested
Protein efficiency ratio (PER)

94. Animal foods are superior to
vegetable foods in terms ofː
Digestibility coefficient
Biological value
Net protein utilization
Protein efficiency ratio

95. Animal proteins are said to be first class
proteins or proteins of high biological
value
Vegetable proteins are described as
second class proteins or proteins of low
biological value

96. Ideally, animal proteins should provide at
least half of the protein requirement
However, animal foods are much more
expensive than vegetable foods
They are beyond the reach of large
sections of population

97. As it is difficult to raise the consumption of
animal foods, protein quality of vegetable
foods should be improved
The drawback of most of the vegetable
proteins is absence or deficiency of one
or more essential amino acids

98. Essential amino acid content of
vegetable foods can be improved by:
Mutual supplementation
Fortification with amino acids

99. An essential amino acid deficient in one
vegetable food may be present in another
If the two are taken together, all the
essential amino acids can be obtained
This is known as mutual supplementation
Mutual supplementation

100. Some useful combinations for mutual
supplementation are:
• Wheat + pulses
• Rice + pulses
• Wheat + groundnuts
• Rice + groundnuts
• Wheat + soya bean
• Bengal gram + sesame
• Cereals + legumes + leafy
vegetables

101. Fortification with amino acids
The limiting amino acid is added to the
food
The limiting amino acids in most of the
vegetable proteins are:
Lysine
Methionine
Threonine
Tryptophan

102. Lysine and methionine are being
manufactured on commercial scale
These can be used for fortification of
vegetable foods
Fortification has been shown to improve
the PER of vegetable foods

103. Protein efficiency ratio (PER) of some
vegetable foods before and after fortification
Wheat (before fortification) 1.3
Wheat (fortified with lysine) 2.4
Rice (before fortification) 1.7
Rice (fortified with lysine+threonine) 2.0
Maize (before fortification) 1.0
Maize (fortified with lysine+threonine+tryptophan) 2.2
Soya bean (before fortification) 0.9
Soya bean (fortified with methionine) 3.2
Food PER

104. Protein requirement is more in growing
age than in adult life
Protein requirement is also increased in
pregnancy and lactation
Indian requirements have been laid
down by ICMR
Protein requirement

106. Lipids are commonly known as fats and
oils
Fats are solid at room temperature while
oils are liquid at room temperature
Fats and oils are chemically triglycerides
Triglycerides are the major lipids present
in food
Lipids

107. Small amounts of phospholipids, glyco-
lipids, cholesterol etc are also present in
food
Except for polyunsaturated fatty acids
(PUFA), all the lipids can be synthesized
in the body

108. PUFA which cannot be synthesized in
the body are known as essential fatty
acids (EFA)
Thus, one major function of dietary lipids
is to provide essential fatty acids

109. • Carriers of fat-soluble vitamins
• Concentrated source of energy
• Make the food palatable
• Spare proteins from being used as
an energy source
Some other functions of lipids are:

110. Therefore, a certain amount of
lipids must be present in the diet
The quantity and nature of dietary
lipids should be such thatː
Our requirement of EFA and
energy is met
Atherosclerosis is not promoted

111. Atherosclerosis is promoted by
excessive intake of:
Triglycerides
Cholesterol
Saturated fatty acids
PUFA protect against atherosclerosis

112. The lipid content and composition of diet
should be determined keeping the follow-
ing points in mind:
Total lipid intake should be just
enough to meet the requirements
Cholesterol intake should be less
than 300 mg per day
PUFA should replace saturated
fatty acids to the extent possible

113. ICMR (1981) has recommended that 20%
of the total calorie requirement should be
provided by lipids
EFA should provide at least 3% of calories
in adults, and 5-6% in infants, children,
and pregnant and lactating women
Lipid requirement

114. Lipids may be present in food as visible fat
or invisible fat
Visible fat
Invisible fat

115. Oils, butter, ghee etc, which are pure
lipids, are known as visible fat
Lipids present in milk, egg, meat, fish,
pulses etc constitute invisible fat
According to ICMR, invisible fat should
comprise half of the total lipid intake

118. PUFA essential for us are linoleic acid,
a-linolenic acid and arachidonic acid
Most of the PUFA present in oils and fats
is linoleic acid
Among vegetable oils, the only good
source of a-linolenic acid is soya bean oil

119. a-Linolenic acid is present in green leafy
vegetables also
The requirement for a-linolenic acid is
very small
Arachidonic acid requirement is even
smaller which is easily obtained from
invisible fat

120. Hydrogenated vegetable oils became a
popular cooking medium in poor strata
because of their better keeping quality
During hydrogenation, unsaturated fatty
acids are converted into saturated fatty
acids

121. Thus, EFA content of oils is decreased
during hydrogenation
The cis double bonds may be converted
into trans double bonds
The trans double bonds promote athero-
sclerosis

122. Cholesterol content of foods is also
important
Excess cholesterol in circulation promotes
atherosclerosis
Cholesterol is present only in animal foods

124. No carbohydrate is really essential for
human beings
All the carbohydrates can be synthesized
by human beings
Still carbohydrates are required in diet as
they are a cheap source of energy
Carbohydrates

125. Carbohydrates are present in
food generally in three forms:
Starch Sugars Fibre

126. Starch is the most abundant carbohydrate
in food
It is present in cereals, pulses, roots, tubers
etc
Starch

127. Sugars
Sugars include:
Monosaccharides
e.g. glucose,
fructose and
galactose
Disaccharides
e.g. sucrose,
maltose and
lactose

128. Lactose is present in milk only
Other sugars are present in fruits,
vegetables etc
Cane sugar (sucrose) is man-made and
is used as a sweetening agent

129. Remnants of edible part of plants that are
resistant to digestion constitute fibre
Cellulose is a fibre present in most
vegetable foods in varying proportions
Other fibres include hemicellulose, pectin,
lignin, inulin, gums, mucilages etc
Fibre (roughage)

130. Presence of fibre in diet is important as
it stimulates peristalsis and prevents
constipation
A high fibre intake has been reported to
decrease the incidence of colorectal cancer,
hypertension, diabetes mellitus etc

131. No quantitative requirement can be laid
down for carbohydrates
First, the total energy requirement of an
individual is calculated
Then, the contribution of proteins and
lipids is deducted
The remaining energy should be provided
by carbohydrates
Carbohydrate requirement

133. Carbohydrates have a protein sparing
effect
Adequate carbohydrate intake spares the
proteins for tissue formation rather than
being used as a source of energy

134. The daily food intake constitutes diet
The diet should meet the daily require-
ment of all the essential nutrients
There should be neither a deficiency nor
an undue excess of any nutrient
These objectives can be achieved from a
balanced diet
Balanced diet

135. A balanced diet contains a variety of foods
in such quantities and proportions that the
requirements for energy and all essential
nutrients are adequately met, and a small
provision of extra nutrients is made to tide
over short durations of lean intake
Definition

136. The major food groups in a diet are:
• Cereals
• Pulses
• Vegetables and fruits
• Milk
• Fats and oils
• Sugar

137. In addition to the usual food groups, a
non-vegetarian diet contains:
• Eggs
• Meat
• Fish

138. Each of the food groups has a specific
nutritional profile
Some are rich in carbohydrates, some in
proteins and some in vitamins and
minerals

139. The daily diet should contain each of the
food groups
The quantities of food groups should be
such that our daily requirements of energy
and all the essential nutrients are met
Before planning a diet, we should know the
nutritional profile of each food group

140. Cereals
Cereals are the largest component of an
average diet

141. The major cereals are wheat, rice and
maize
Millets, which are smaller grains, are also
included in this group
The important millets are sorghum and
pearl millet

142. Cereals are a major source of energy
The energy provided by them is about 350
kcal/100 gm
The most abundant nutrient in cereals is
carbohydrate which is present as starch
It makes up 70-80% of the weight of
cereals

143. The protein content of rice is about 7%
while that of other cereals is 10-12%
The proteins present in cereals are deficient
in lysine
Some are deficient in threonine also
Maize is, in addition, deficient in tryptophan

144. The fat content of cereals is low
Fat content of rice, wheat and sorghum is
less than 2%
Fat content of maize and pearl millet is
less than 5%

145. The cereals contain significant amounts of
minerals
But absorption of calcium, phosphorus and
iron from cereals is not very efficient
Several members of B-complex group of
vitamins are present in cereals
These are present mainly in the outer layer
of the grain

146. The removal of outer layer
of cereals leads to:
Significant loss of vitamins
Some loss of proteins

147. Pulses
A major source of proteins for vegetarians

148. The pulses contain 60-65% carbohydrate,
22-24% protein and less than 5% fat
Proteins present in pulses are deficient in
methionine
But pulses and cereals supplement the
limiting amino acids of each other

149. Energy provided by pulses is about 350
kcal/100 gm
Minerals and some members of B-complex
group of vitamins are also present in pulses
Germinating pulses contain vitamin C, and
higher concentrations of B-complex vitamins

150. Protective foods
Vegetables and fruits

151. Vegetables and fruits are called protective
foods as they are rich in vitamins and
minerals
They are generally a good source of fibre
too
Some vegetables and fruits contain signi-
ficant amounts of carbohydrates also

152. The vegetables are generally divided
into three groups:
Roots and
tubers
Green
leafy
vegetables
Other
vegetables

153. Roots and tubers
Include potatoes, sweet potatoes,
colocasia, onion, carrot, radish etc

154. Potatoes and sweet potatoes are fair
sources of carbohydrates
Potatoes contain some vitamin C also
Carrot is rich in carotenes

155. Green leafy vegetables
Include spinach, coriander leaves,
mustard greens, mint, cabbage etc

156. Green leafy vegetables provide B-complex
vitamins, vitamin C, carotenes, calcium,
iron and other trace elements
They also add roughage to the diet

157. Other vegetables
These are vegetables other than green
leafy vegetables, and roots and tubers

158. The other vegetables include tomatoes,
okra, cauliflower, capsicum, cucumber,
pumpkin, egg plant etc
These are rich in vitamins and minerals
They also add roughage to diet

159. Fruits also belong to the same group as
vegetables
They are excellent sources of vitamins
and minerals
An added advantage of fruits is that they
are generally eaten raw
Therefore, the heat-labile vitamins present
in them are not destroyed

160. Milk is a nearly balanced diet by itself
Milk

161. Milk contains all the essential nutrients
except vitamin C and iron
Milk proteins contain all the essential
amino acids
The carbohydrate present in milk is
lactose which is advantageous

162. Lactose (milk sugar) is particularly useful
for infants and children
It provides galactose for the formation of
nervous tissue
CH2OH
OH
HH
H
HOH
O
H OH
O
CH2OH
H
H
OH
H
HOH
O
H OH
Lactose
Galactose Glucose

163. Infants should be fed mother’s milk as long
as possible
Antibodies (secretory IgA) against many
pathogens are present in mother’s milk

164. Fats and oils
Fats and oils are pure lipids
Most forms of cooking require some fats
and oils

165. Fats make the food palatable
Excess of oils and fats should be avoided
Vegetable oils should be preferred as they
provide essential fatty acids

166. Sugar
Cane sugar is used as a sweetening
agent
It is pure sucrose, and provides
nothing except calories
Jaggery provides some iron also

167. Eggs
Egg is an excellent food
It has all the essential nutrients except
carbohydrates and vitamin C
Egg proteins are considered to be the
best out of all the proteins

168. Raw egg contains avidin
Avidin forms a complex with biotin
This prevents the absorption of biotin
Avidin is heat-labile

169. Cooking inactivates avidin
Inactive avidin doesn’t hamper biotin
absorption
Cooking also coagulates albumin and
globulin
This makes them easy to digest

170. Egg yolk is rich in cholesterol
Excess of cholesterol increases the
risk of coronary artery disease

171. Blood
vessel
wall
Blood
flow
Cholesterol
build up
Total
block
Normal blood flow Decreased blood flow No blood flow

172. Persons having risk of coronary artery
disease should avoid egg yolk
They can take egg white which has high
quality proteins but no lipids

173. Meat
Meat is another good source of high-
quality proteins
The protein content of meat is about 20%

174. Meat is a good source of iron also
Absorption of iron is much better from
meat than from vegetable foods
Many other minerals and vitamins are
present in meat

175. Liver is rich in many nutrients
Fat content of meat is variable, and
contains mostly saturated fatty acids
Organ meats are rich in nucleic acids,
and can aggravate gout

176. Fish
Fish is also a good source of proteins of
high biological value
Protein content of fish is about 22%

177. Fish is rich in vitamins A and D
Fat present in fish contains a-linolenic acid
and some other w-3 unsaturated fatty acids

178. Daily diet
All the food groups should be included in
the daily diet
Their inclusion in proper proportions can
provide all the essential nutrients

179. Within a group, one food can be replaced
by another
Rice can be replaced by wheat and vice
versa
One pulse can be replaced by another

180. Attention should also be paid to the cost of
a food item
A costly food item is not necessarily
superior

182. Balanced diet for adult women (vegetarian)
Sedentary Moderate Heavy
work work work
Cereals (gm/day) 410 440 575
Pulses (gm/day) 40 45 50
Roots and tubers (gm/day) 50 50 60
Leafy vegetables (gm/day) 100 100 100
Other vegetables (gm/day) 40 40 50
Milk (ml/day) 100 150 200
Oil and fat (gm/day) 20 25 40
Sugar and jaggery (gm/day) 20 20 40

187. Adjustments for non-vegetarians
Eggs, meat and fish are protein-rich foods
They can replace pulses wholly or partially
A non-vegetarian diet contains eggs, meat
and fish

188. Half of the requirement for pulses can be
replaced by one egg and 5 gm of oil/fat
Or it can be replaced by 30 gm of meat or
fish and 5 gm of oil/fat
The entire requirement for pulses can be
replaced by two eggs and 10 gm of oil/fat
Or the pulses can be replaced wholly by
50 gm of meat or fish and 10 gm of oil/fat

189. Food
pyramid

190. Diseases resulting from inadequate or
excessive intake of nutrients are known
as nutritional disorders
Disorders arising from inadequate or
excessive intake of proximate principles
will be discussed here
Nutritional disorders

191. Kwashiorkor occurs when the diet is
severely deficient in proteins but adequate
in calories
This usually occurs when infants are
weaned from breast milk and top feeding
is started
Kwashiorkor

192. If the diet is very poor in proteins, it fails to
meet the protein requirements
Proteins are required for tissue formation
Hence, formation of tissues is decreased in
the growing child

193. Kwashiorkor results in growth retardation
and muscle wasting
Skin becomes hyper-pigmented in some
areas and hypo-pigmented in others
Hair becomes brittle and discoloured

194. Decreased apolipoprotein synthesis
leads to fatty liver
Anaemia develops due to decreased
globin synthesis
There is a marked decrease in serum
albumin concentration
This usually leads to generalized
oedema

195. Oedema masks muscle wasting, and gives
a rounded appearance to the child
Diarrhoea is common and leads to losses
of nutrients including vitamins
Concentrations of amino acids and urea in
serum are decreased

196. A child with kwashiorkor

197. Kwashiorkor can be prevented by correct
feeding practices in the post-weaning period
The post-weaning diet should include:
A small amount of animal foods (milk,
skimmed milk, egg, meat, fish etc)
Or a mixture of cereals and pulses

198. Once kwashiorkor has occurred, it can be
treated by increasing the protein intake
The protein intake should be raised to a
level that proteins supply 20% of the total
energy

199. Protein intake may be raised by addition of
skimmed milk powder to the diet
Or one of the following mixtures may be
added to the diet:
Three parts of groundnut flour and
one part of Bengal gram flour
Three parts of wheat flour and one
part of cotton-seed flour

200. Marasmus results from a generalized
decrease in food intake
There is deficiency of calories as well as
proteins in the diet
The available proteins are used as a source
of energy rather than for tissue formation
Marasmus

201. Growth is retarded in marasmus
There is muscle wasting
Subcutaneous fat disappears
The child gives a shrunken appearance

202. A child with marasmus

203. Diarrhoea is common and aggravates the
problem
Diarrhoea results in loss of nutrients from
the intestines
Multiple vitamin deficiencies and infections
commonly occur

204. Marasmus is treated by:
• Increasing the energy and protein
intake
• Supplementing vitamins and
minerals
• Correcting dehydration
• Controlling the infections

205. Starvation can occur due to scarcity of
food in famine-affected areas
It can also occur in ship-wrecked sailors
and in travellers stranded in desert
Sometimes, it may be due to a psychiatric
condition, anorexia nervosa
Or it may result from voluntary fasting
Starvation

206. When food intake stops, body begins to
use stored nutrients
Triglycerides are the major storage form
of energy
The other storage forms are proteins and
glycogen

208. Even if the starving person is at rest,
1,600 kcal/day will be required for BMR
The carbohydrate reserves will not last
even a day
The lipid reserves can last 50-60 days
The protein reserves can last 10-15 days

209. After glycogen depletion, lipids become
the major energy source
Some proteins are also utilized for
gluconeogenesis:
To provide glucose to
brain
To form citric acid cycle
intermediates

210. Major metabolic readjustments occur to
prevent wastage of proteins
Unnecessary enzymes are not synthesized
These include enzymes required for diges-
tion & synthesis of fatty acid, urea etc
Synthesis of gluconeogenic enzymes is
increased

211. As availability of glucose is low, fatty acid
oxidation increases
This increases the production of ketone
bodies
Ketone bodies begin to appear in urine 3-
4 days after complete starvation
The brain tissue adapts itself to use
ketone bodies as a source of energy

212. When protein reserves decrease, gluco-
neogenesis fails to meet the requirements
Excessive fatty acid oxidation results in
severe ketosis
Ketosis disturbs the acid-base balance and
electrolyte balance
Death usually occurs from acidosis and
electrolyte imbalance

213. Treatment of starvation consists of
resumption of feeding
But digestive enzymes are deficient and
intestinal mucosa may be atrophied
Therefore, re-feeding should begin with
glucose-water or fruit juices

214. Skimmed milk can be given later
Subsequently, bread, biscuits, potatoes
and eggs may be given
Normal diet may be resumed after a few
days

215. Severely starved persons may require
intravenous fluids
Correction of acid-base and electrolyte
imbalance may also be required

216. Obesity may be defined as accumulation
of excess fat in the body
In some subjects, it is due to hereditary
factors or hormonal disorders
But in majority of subjects, it is due to
excessive calorie intake
Obesity

217. When calorie intake exceeds
calorie expenditure:
The extra calories are
converted into fat
Fat is deposited in fat
depots

218. Obesity increases the susceptibility to:
• Dyspnoea on exertion
• Hypertension
• Diabetes mellitus
• Coronary artery disease
• Cerebral thrombosis
• Gall bladder stones
• Arthritis of weight-bearing joints
• Difficult surgery and labour

221. Accurate measurement of skin-fold thickness

222. Another method is based on standard
height and weight charts
Height and weight charts of Life
Insurance Corporation of India are taken
as standard in India
A body weight 10% above the ideal body
weight is diagnostic of obesity

223. Weight in kg
BMI =
[Height in metres]2
A simpler alternative is calculation of
body mass index (BMI)
BMI can be calculated from height and
weight

224. BMI nomogram
Weight (kg)Height (metres)
BMI

225. The normal BMI is 20-25 in males and
19-24 in females
A BMI above 30 signifies obesity

226. Obesity is treated by decreasing energy
intake and increasing energy expenditure
Energy expenditure can be increased
only by increasing physical activity

227. Walking at brisk speed increases the
energy expenditure to 300 kcal/hour
During running, swimming and heavy
exercise, 500-600 kcal are spent per hour

228. The energy intake should be reduced to
1,000 kcal/day
This should be continued until the ideal
body weight or BMI is achieved

229. Protein intake should be maintained at
1 gm/kg of body weight
Fats should provide not more than 10%
of total calories
The remaining calories should be
provided by carbohydrates

230. Intake of sugar and jaggery should be
restricted to 15 gm/day or less
Potatoes and sweet potatoes should be
excluded from the diet
Other vegetables - raw, boiled or
steamed - may be taken as desired

231. Fruits (200-250 gm/day) and skimmed
milk (400 ml/day) should be included in
the diet
Vitamin supplements may be given in the
form of one multivitamin tablet daily