Basics of Nutrition

The basic objectives of a food plan are as follows:

  • Provides nourishment for normal activity and growth
  • Helps attain and maintain normal weight
  • Is easily available and low cost
  • Provides satisfaction
  • Supplies a balanced daily requirement of:
    • Calories
    • Carbohydrates, Protein & Fat
    • Vitamins & Minerals
    • Roughage
    • Water


Food provides energy and other nutrients essential for vital functions of the body, during periods of rest, activity, and growth. The amount of food and type of food we eat determines the amount of energy we receive. Excess unutilised calories are stored in the body as fat for future use.

  • Energy is produced by utilization of food in the body. Calorie is a measure of heat energy.
  • The SI (standard International) unit of energy is Joules (J)
  • Physiologically energy is measured as Kilo Joules.
  • Physiological Calorie is a Kilo Calorie, but referred to as Calories (Cal).
  • 1 Kcal = 4.2 KJ


Carbohydrates are the major source of energy in the body. Carbohydrates are broken down to form glucose. It is the main nutrient that raises blood sugar.

Carbohydrates are present in:

  • Sugar (refined carbohydrate) Sugar, Molasses, Honey
  • Starch (complex carbohydrate) Bread, Chappati, Rice, Dal, Pasta, Potatoes
  • Fruits and vegetables
  • Milk

1gm of carbohydrate gives 4 calories.

  • Sugars are rapidly digested and absorbed in the body. They cause rapid and large increase in blood sugar level.
  • Starchy foods like roti, rice, and bread are not rapidly digested and absorbed in the body. Blood sugar level does not increase so rapidly.


One of the classes of food that is necessary for growth and repair of tissues. Found in fish, meat, eggs, milk and some vegetables.

  • Proteins provide amino acids – the building blocks for body tissues, hormones and other substances.
  • Protein rich foods are eggs, meat, fish, milk, pulses etc.
  • 1 gm of protein gives 4 calories.
  • Animal source – provide better quality protein. Egg, milk, meat, fish, poultry are protein rich foods from animal source.
  • Plant source – individually provide less good quality protein but when two complimentary types of plant proteins are eaten together the quality improves (dal+roti or dal+rice or iddli). Pulses, Cereals, Nuts are sources of plant protein.


Fat is the most concentrated source of energy

Fats in the diet are:

  • Saturated – Ghee, butter, margarine, hydrogenated fat (vanaspati).
  • Poly-unsaturated – Safflower oil, sunflower oil
  • Mono-unsaturated – Olive oil, groundnut oil, mustard oil, sesame oil.
  • Cholesterol – egg yolk, ghee, butter.
  • Trans fatty acid – biscuits, cakes, mixture.
  • Oilseeds and nuts – (monounsaturated) – Peanuts, Almonds, Walnut.
  • 1 gm of fat gives 9 calories.


Vitamins are a group of organic substances present in minute amounts in food and are vital for good health.

  • A, B group, C, D, E, K is the different groups of vitamins. Vitamins can be water or fat soluble.
  • When a balanced meal with the correct proportions of carbohydrates, proteins, fats and plenty of fruits and vegetables is taken, the body automatically receives all the necessary vitamins.


Minerals like vitamins are vital for good health and are present in large amounts in the body (bones, blood). Minerals are part of the food we eat. The different minerals found in food are – Calcium, Phosphorous, Iron, Sodium, Potassium, and Magnesium. Each mineral has a specific role to play in the body.

Trace elements – Iodine, Zinc, Copper, Chromium, Manganese, Molybdenum, Fluoride, Selenium, Cobalt, Silicon, Arsenic, Nickel, and Vanadium.



Antioxidants are good for health, they protect against heart disease and possibly other complications.

“Antioxidant” is a classification of several organic substances, including vitamins C and E, vitamin A (which is converted from beta-carotene), selenium (a mineral), and a group known as the carotenoids. Antioxidants neutralize free radicals by donating one of their own electrons.  Free radicals are the natural by-products of many processes within and among cells. Free radicals are also created by exposure to various environmental factors, such as tobacco smoke and radiation. They cause damage to cells and if the production of free radicals is excessive it can lead to various complications like heart disease and cancer.

Antioxidants on the other hand act as scavengers, helping to prevent cell and tissue damage that could lead to cellular damage and disease.

Evidence suggests that antioxidants are important to good health. Eating around 5 servings of fruit and vegetables, a day provides the necessary antioxidant health benefits to the body.

The different groups of antioxidants are:

  • Tocopherols – good sources include wheat germ, nuts (almonds, walnuts and peanuts), seeds, whole grains, green leafy vegetables, vegetable oil like safflower oil, corn oil and fish-liver oil
  • Cartenoids – good sources include carrots, squash, broccoli, sweet potatoes, tomatoes, kale, collards, cantaloupe, mango, peaches and apricots
  • Vitamin C good sources include citrus fruits, green peppers, broccoli, green leafy vegetables, strawberries, raw cabbage and potatoes.
  • Flavonoids good food sources are broccoli, pomegranate, lime, soy bean, oranges, lemons, apples, white grapefruit, onions, and chocolates



Water is the most essential nutrient the body needs.

  • 40-60% the body weight and approximately 70% of muscle composition is water.
  • 8-10 glasses of water are recommended throughout the day for an average person.