Nutrition is the science of food and its relationship to health. The following three processes are involved in the utilization of food in our bodies.

Ingestion: It implies intake of food (by mouth)
Digestion: After ingestion food is digested to make it absorbable. It is achieved by enzymes present in our mouth (saliva), stomach, and intestines.
Absorption: Digested food gets absorbed and passes from our intestines into the blood circulation and lymphatic system for distribution all over the body.

Food has major physiological functions as follows:

• Provides energy for body functions. •
• Nutrients build and maintain body tissues. •
• Safeguarding body against diseases. •
• Regulating body functions.

The psychological function of food includes the following:

• Satisfying hunger and taste buds. •
• Provides comfort in a depressive mood. •
• Used as a reward or punishment e.g. good or bad food.


There are a variety of nutrients that are supplied through the foods. Nutrients play a critical role in health and disease. Each nutrient performs a specific function in the body. The absence of a particular nutrient can cause a specific deficiency disorder.

Functions of nutrients:

  • Energy production for physical
  • Growth, development and •
  • Resistance to infection and protection from •
  • Control of temperature, blood pressure, metabolism, and waste

Macronutrients –

These are organic nutrients required in large quantities. These are proteins, fats, and carbohydrates.

  1. Proteins- These are of the greatest importance in humans Proteins are composed of carbon, hydrogen, oxygen, nitrogen and sulfur, phosphorus, iron, and other elements in varying amounts. These are built of amino acids. The human body requires 22 amino acids. Of


these 8 are called “essential” because the body cannot synthesize them in sufficient quantity. The essential amino acids are as follows: 1) Isoleucine 2) Leucine 3) Lysine 4) Sulphur-containing amino acids (methionine + cysteine) 5) Phenylalanine Tyrosine 6) Threonine 7) Tryptophan, and 8) Valine.

Functions of Proteins:

  • For growth and development: since they provide the building material e. the amino acids
  • For repair of body tissues and their maintenance
  • For the synthesis of antibodies, enzymes and The body requires protein to produce anti-bodies.

Sources of proteins:

  • Animal Source: found in milk, meat, eggs, cheese, and fish.
  • Plant Source: found in pulses (legumes) cereals, beans, nuts, oil-seed cakes, etc
  • Protein Requirements: Usually 1.0 gm protein/ kg body weight is needed for an Indian adult.


Fats are composed of carbon, hydrogen, and oxygen. They are composed of fatty acids. Fats are again classified into saturated and unsaturated fats. In general, animal fats are “saturated” fats; vegetable oils and fats are “unsaturated” fats.

Functions of Fats:

  • It is the source of One gram of fat and supplies 9 calories of energy.
  • Fats are carriers of fat-soluble vitamins, g. vitamins A, D, E, and K.
  • Fats provide cushioning for many organs in the body (heart, kidney, intestine )

Sources of Fats:

  • Animal sources: These are ghee, butter, fat from meat, fish oil, etc.
  • Vegetable sources: these are various vegetable oils such as groundnut, ginger, mustard, cottonseed, safflower (kardi), and coconut

Fat requirements:

  • In developed countries, dietary fats provide 30–40 % of total energy Ideally only 20–30 % of total dietary energy should be provided by fats.


These are the main source of energy, providing 4 kcals per gram. Carbohydrate is also essential for the oxidation of fats and for the synthesis of certain non-essential amino acids. There are 3 main sources of carbohydrates, viz., starches, sugar, and cellulose.

Micronutrients –

  • Micronutrients are needed only in minuscule amounts, these substances enable the body to produce enzymes, hormones, and other substances essential for proper growth and
  • There are two types of Micronutrients, these are Vitamins and



  • A suitable diet for the individuals and families shall be as per the local food items available, individual dietary habits, and as per the economic status of families. The diet should also satisfy hunger and
  • It provides 50–60% energy from carbohydrates (preferably complex carbohydrates), 10– 15% from protein, and 20–30% from oils and

Aims of Meal Planning

  • Fulfill the nutrition needs of an individual or members of a
  • Invest in nutrient-dense food items rather than energy-dense
  • Help in the purchase, preparation, and service of appropriate food
  • Provide variety in the diet through proper selection of

Diet Plan for Different Age Groups

Diet Plan for a Toddler: Children aged 1–4 years can eat the same foods as an adult, about half the amount. Healthy foods are good to include. But do not forget to remind the

parents to ensure that their children drink plenty of fluids throughout the day. Try also to make foods fun and easy to eat.

Diet Plan for Children aged 5–12 yrs: They are still developing both physically and mentally. They also need good nutrition. Calcium-rich foods, sources of essential fats; high protein foods, and slow-released carbohydrate sources need particular attention. They should be encouraged to eat the same meal as the whole family. Sitting down together is also important to help behavioral development and for the re-enforcement of family values.

Diet Plan for Adolescents: Adolescence ranges from 10–19 years of age. If they are into sports or heavy physical activities, they need to eat more. Good calcium and iron intake are important in girls. They should avoid junk foods.

Diet Plan for an Elderly Person: One particular concern in the elderly is obtaining sufficient fluid intake. Some old people also have difficulty in passing stools; therefore a good fiber intake is encouraged.


The nutritional status of an individual is the result of many interrelated factors. It is influenced by the adequacy of food intake both in terms of quality and quantity and also by the physical health of the individual.

Objectives of Nutritional Assessment –

  • To obtain information on the extent of nutritional problems of a
  • To identify the population group ‘at risk’ or in greatest need of
  • To develop a nutrition program that meets the needs defined by the
  • To evaluate the failure or success of nutrition
  • To assess the degree of malnutrition in preschool and school going

Methods of Assessment This involves various techniques and methods.

  1. Clinical Examination: It is also the most practical method of ascertaining the nutritional status of a group of individuals. There are a number of physical signs, some specific and many When two or more clinical signs/characteristics of a deficiency disease are present simultaneously, their diagnostic significance is greatly enhanced.

Signs used in the nutritional survey:

  • Not related to nutrition, g. alopecia, pyorrhoea, pterygium.
  • That needs further investigation (molar pigmentation, coined vascularisation, geographic tongue)
  • Known to be of value, g. angular stomatitis, Bitot’s spot, calf tenderness, absence of knee or ankle jerks (beriberi), enlargement of the thyroid gland (endemic goiter), etc.

2. Laboratory and Biochemical Assessment:

Hemoglobin estimations: It is the most important laboratory test that is carried out in nutritional surveys. It is a useful index of the overall state of nutrition. Stools and urine be examined for intestinal parasites. History of parasitic infestation, chronic dysentery, and diarrhea provide useful information about the nutritional status. Urine should also be examined for albumin and sugar.

Biochemical test: These may be applied to measure individual nutrient concentration in body fluids (e.g. serum retinol, serum iron) or to detect abnormal amounts of metabolites in urine (iodine). Biochemical tests are time-consuming and expensive. They cannot be applied on a large scale, e.g. in the nutritional assessment for the whole community.

  1. Assessment of Dietary Intake: Direct assessment of food consumption involves dietary surveys which may be household inquiries on individual food consumption surveys. A diet survey may be carried out by one of the following methods:
    • Weight of raw foods
    • Weighing of cooked foods

Nutrition Quiz Questions and Answers

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