Nutrition is the science of food and its relationship to health. A balanced diet provides calories from carbohydrates, proteins, and fats in a 60:20:20 ratio and supplies micronutrients. Carbohydrates like starch are the primary energy source and provide 4 calories per gram, while proteins build body tissues and fats supply 9 calories per gram and aid nutrient absorption. A balanced diet containing fibers, unsaturated fats like omega-3s, and less than 250mg of cholesterol daily supports health.

1. IMPORTANCE OF
NUTRITION
&
ITS PROXIMAL PRINCIPLES

2. Nutrition
 Is defined as the
science of food and
its relationship to
health.

3.  It is concerned
primarily with the part
played by the nutrients
in body growth,
development and
maintenance.

4. Good nutrition means
maintaining nutritional
status that enables us
to grow well and enjoy
food health that is
intake of a well balance
diet.

5. WHAT IS NUTRITION?
NUTRITION is a
science of food &
its relationship to
health.

6. WHAT IS HEALTH ?
Health is a state of
complete physical,
mental & social well
being & not merely an
absence of disease.

7. BALANCED DIE

8. A Balanced diet is a kind of a
diet which contains variety of
foods in such quantities and
proportions that the bodies
need for energy .
 Like -- Carbohydrates, Lipids,
Proteins, Vitamins & minerals

9. A Balanced diet should
contain and obtain
calories from
carbohydrates, proteins
and fats in the ratio of
60:20:20.

11. WHAT IS A CALORIE ?
The energy content of food
materials is measured in calories.
How is a Calorie defined?
1 calorie is the heat required to
raise the temperature of 1 g of
water through 1⁰c.

12. CALORIE IS A SMALL UNIT
Since it is a very small unit, in
medical practice, the energy
content is usually expressed in
kilocalorie (Kcal) which is equal to
1000 calories.
 The maximum available energy
contained in a food can be
measured by burning it in an
atmosphere of in a bomb
calorimeter.

13. THE PROXIMAL PRINCIPLES
The Proximal Principles of
Nutrtion are mainly three
Carbohydrates
Proteins
Fats
To a certain extent in small
quantities Vitamins and
minerals

14. NUTRITIONAL IMPORTANCE OF
CARBOHYDRATES
The dietary carbohydrates provide
a major fraction of the body’s
energy needs.
1.Ideally –Carbohydrates may
provide about 60-65% of total
calories.
There are two groups of dietary
carbohydrates

15. A. AVAILABLE CARBOHYDRATES
These can be metabolized by the
body to give energy
e.g, starch & sugars
Carbohydrates provide 4kcal/g
1.Cane sugar (100%-CHO)
2.Rice (80%)
3.Wheat (70-80%)
4.Bread (50-60%)
5.Honey (80%)
6.Potatoes (25%)
CHO in
Common
foods

16. THE MAJOR DIETARY
CARBOHYDRATE
 Starch is the major dietary
carbohydrate
It is digested by amylase to
maltose & then hydrolyzed to
glucose

17. Glucose is the major source
of energy (fuel) for most
organs & tissues
Brain cells & R.B.C ‘s are
wholly dependent on
Glucose for energy.
Excess (starch & glycogen)
is converted to fat & stored.
 Cane sugar is mainly used
as a sweetening agent

18.  Sucrose is easily fermented by the
bacteria present in dental plaque, which
would damage the enamel & leads to
tooth decay and dental caries.
In adults consumption of large
quantities of refined sugars tend to
produce a sudden rise in blood glucose
level. This will also lead to excessive
calorie intake
.

19.  Sucrose consumption
also results in
increased levels of
plasma lipids.
 While prescribing
diets for diabetics & for
weight reduction,
sucrose should be
strictly avoided

20. B. UNAVAILABLE CARBOHYDRATE
These cannot be assimilated &
constitute only the dietary fibers
 Dietary fiber are also called
unavailable ,indigestible
carbohydrates
In the diet they are necessary to
maintain the normal motility of the GIT
e.g Cellulose, Hemi cellulose, Lignin &
Pectins.

21. The Fiber requirement per
day is about 30g.
 Inclusion of fiber rich foods in
weight reducing diets is found to
be helpful, since it provides a
feeling of fullness without
consumption of excess calories.

22. The beneficial effect is more
with soluble fiber present in
vegetables & only a diet having
plenty of vegetables & green
leaves will have the desired
effects.

23.  A diet rich in fiber improves
bowel motility, prevents
constipation and decreases
re- absorption of bile acids
Thereby lowering cholesterol
level & improves glucose
tolerance. for Hypoglycemic &
Hypo lipidemic effect.

24. PROTEINS
 Proteins form the building blocks
for body tissues.
 Only 10-15% of total energy is
derived from proteins.
 When enough carbohydrates are
present in the diet. The amino
acids are not used for yielding
energy.
 This is known as the protein
sparing effect of carbohydrates

25. During starvation, amino
acids may act as energy
sources.
Proteins are the only source of
essential amino acids.
As per WHO recommendation
the safe levels of protein intake for
an adult is 0.75-0.8 g /kg / day or
in more simpler terms
 1gm / kg body weight

26. NUTRITIONAL IMPORTANCE OF
PROTEINS
 For the synthesis of body proteins all
essential amino acids should be
supplied in adequate quantities at the
same time.
Cystine & Tyrosine can be
synthesized, when Methionine &
phenylalanine are available.
Thus the requirement of the precursor
amino acid is determined by the
availability of the product .

27. The remaining amino acids can be
synthesized provided there is enough
supply of proteins in total.
Only 3 amino acids Alanine, Aspartic
acid & Glutamic acid are truly
dispensable, as they can be synthesized
from pyruvate, Oxalo acetate & α keto
glutarate respectively & these
precursors are generally available in
plenty.

28. LIMITING AMINO ACIDS
Certain proteins are deficient in 1 or
more essential amino acids. If this
particular protein is fed to young rat
,as the only source of protein, it fails
to grow.
This deficient amino acid is said to
be limiting amino acid
 ( which limit weight gain).

29. PROTEIN LIMITING AMINO
ACID
PROTEIN
SUPPLEMENT
TO RECTIFY
DEFICIENCY
RICE Lysine,
Threonine
Pulse protein
WHEAT Lysine,
Threonine
Pulse protein
GELATIN Tryptophan Milk protein
ZEIN Tryptophan
Lysine
Meat protein
BENGAL GRAM Cystine,
Methionine
Cereals

30. Nutritional Importance of
Lipids
Provides energy. The calories
derived from fats is 9kcal/g.
Lipids are the storage form of
energy.
They are a favored cooking
medium.

31. A minimum intake of lipids is
essential since the requirement
of fat soluble vitamins &
essential fatty acids are to be
met.
4.Fats increase the taste &
palatability of food.

32. DIETARY FATS MAY BE DIVIDED INTO VISIBLE &
INVISIBLE FATS CONSUMED
Visible Fat
These are consumed as such
e.gs- Butter, Ghee, Oil.
The recommended daily intake of visible fats
is 10% of the total calories or 20g/day.
 During pregnancy 30g/day
 During lactation 45g/day.

33. INVISIBLE FAT CONSUMED IN DIET
Fats present as part of other food
items,
e.g. egg, fish, meat, cereals, nuts
& oil seeds.
Even cereals contain 1g of fat/kg.
More than half of essential Fatty
acids in Indian diet is in the
form of invisible fat.

34. CHOLESTEROL
 Cholesterol a derived lipid and
has atherogenic effect.
People with hypercholesterolemia are
on high risk of coronary artery
diseases. Hence dietary intake of
cholesterol should be restricted.
Food items rich in cholesterol are egg
yolk ,liver , brain & kidney.
Vegetable cereals & pulses do not
contain any cholesterol.

35. On the other hand vegetable
sterols inhibit cholesterol absorption.
Saturated fats raise serum
cholesterol ,while unsaturated fats
lower it.
 Therefore Unsaturated fats (vegetable
oils & fish oils ) are to be preferred.
PUFAS are required for esterification &
excretion of Cholesterol. They reduce the
cholesterol level in blood & are anti -
atherogenic.

36. PUFAS ARE PRESENT IN VEGETABLE OILS & FISH OILS.
THEY ARE ESSENTIAL F.AS & PRECURSORS OF
PROSTAGLANDINS & LEUKOTRIENES.
NAME OF PUFA/EF.AS DIETARY SOURCE
Linolenic acid Vegetable oils
Lanoliec acid ‘’
Archidonic acid ‘’
Timnodonic acid Fish oils

37. The omega 3 F.AS from fish oils decrease the plasma
lipoproteins (VLDL & LDL) & thereby decrease the risk of
CADS ( Coronary artery diseases).
FAT/OILS Saturated Monounsat
urated
Polyunsatur
ated
Butter/Ghee 75% 20% 5%
Safflower 9% 12% 79%
Coconut oil 86% 12% 2%
Ground nut
oil
18% 46% 36%

38. Excess of PUFA may lead to production
of free radicals that may be injurious to
cells.
PUFA should not be more than 30% of
total fat.
Therefore it is essential to take
saturated: monounsaturated:
polyunsaturated F.AS in 1:1:1 ratio.

39. Cholesterol intake should be less
than 250mg/day.
The ideal fat intake is about
15-20% of total calories, out of
which about 25-30% may be PUFA.
This will be a total of about 20-25g
of oils & about 3g of PUFA for a
normal person.

40. TRANS FATTY ACIDS
TFA are atherogenic they lower
HDL levels & elevates LDL levels.
TFA are present in dairy products &
hydrogenated edible oils .
It is widely used in food industry,
since increases the life of fried
food.

41. TFA adversely affect
endothelial functions &
aggravate insulin resistance &
diabetes.
It is high in processed foods &
bakery products, where
hydrogenated vegetable oils are
used for cooking.

42. Thank
You