Components of Food

Food is a nutritive substance taken by an organism for growth work, repair and maintaining life processes. Food is a kind of fuel for the living things. Just as petrol fuel for our car, in the same way, food is a fuel for our body.

The dietary components of food are:

Moreover, these are broadly classified into three groups:

  1. Energy giving: It comprises of carbohydrates & fats, which provides us with most of our energy required.
  2. Body building foods: These are rich in proteins & are involved in growth & repair of body cells.
  3. Protective foods: These are rich in vitamins & minerals & are involved in building up the body's immune system.

Now let us briefly know that why all these components are so important & what all functions they perform.


The carbohydrates in foods are mixtures of carbon, hydrogen and oxygen and can be classified as: a) simple sugars and polysaccharides.

These form the main bulk of diet & are the chief source of energy.

In a balanced diet, 60% of our daily calorie requirement should come from carbohydrates. However the amount can vary from 50%-70%.

Benefits of Carbohydrates 

Dietary Fiber

It is a type of carbohydrate found in vegetables, fruits, & whole grains, which absorbs water & increases bulk of intestinal contents & helps in intestinal movements. Its deficiency leads to constipation. It also lowers cholesterol & helps in weight reduction.

Benefits of Fiber  













  • Sports Drinks
  • Creatine Transport
  • Formulas
  • Energy Bars
  • Soda
  • Weight Gainer
  • Drinks


  • Table Sugar
  • Brown Sugar
  • Maple Syrup
  • Candy
  • Chocolate Bars
  • Cookies


  • Potatoes
  • Rice
  • Grains
  • Pasta
  • Yams
  • Maltodextrin


  • Fruit
  • Endurance Drinks
  • Energy Bars


  • Milk
  • Dairy Products

Soluble Fiber

  • Legumes
  • Fruits
  • Rolled Oats


  • Milk
  • Dairy Products 


  • Beer
  • Cereal
  • Germinating Seeds

Insoluble Fiber

  • Wheat
  • Cereal
  • Vegetables






What is fat?

Fat is a component in food. Fat is an important nutrient for your health. It plays many different roles in your body:

There are different kinds of fat in foods:

The fat in a balanced diet should provide 20-25% of total energy (i.e. 10-20gms). However, young children can utilize & need extra amount of good fats.

Types of Fats



Good / Bad




The bad: saturated fats (try to limit these)

Animal foods (like fatty cuts of meat, beef, chicken, lamb, pork and veal)

Chicken skin.


Coconut, palm and palm kernel oils

Dairy products (like butter, cheese, cream , ice cream and whole milk)



 Most commercially baked products such as biscuits and pastries.

Most deep-fried fast foods

Saturated fatty acids are found in breast milk, and are essential for infants and toddlers. 

It tends to increase blood cholesterol levels. 

Saturated fats cushion and provide energy to the kidneys and, without palmitic fats, important signalling and stabilising processes in the body will falter. When these fats are lacking, cell and organ growth factors become dysfunctional.

7 percent of total calories from monounsaturated fat.

(The AHA also recommends that you limit saturated fat to about 15 to 19 grams per day.)

Monounsaturated fat (can include these in everyday eating)


Nuts and seeds (like cashews, pistachios, almonds, hazel nuts, macadamias and peanuts)

Vegetable oils (like canola, olive, peanut, safflower, sesame and sunflower)

Egg Yolk.

Tea Seed Oil/Tea Oil

MUFAs may not only help people lose fat, but that they also have protective properties that may lower the risk of developing certain diseases, including Type II Diabetes, heart disease, stroke and possibly certain types of cancers. MUFAs are also part of The Portfolio Diet, which is an approach to eating that combines MUFAs with other cholesterol-lowering foods like soy, plant sterols and soluble fiber from things like oatmeal and may reduce blood cholesterol-levels as effectively as prescription statin drugs. MUFAs may be more effective at weight-control than low-fat diets.

15 percent of total calories from monounsaturated fat

POLY UNSATURATED FAT (can include these in everyday eating)



8 percent or less of total calories from polyunsaturated fat intake

Omega-6 Fatty Acids
Linoleic acid

Leafy vegetables, seeds, nuts, grains, safflower oil, sunflower oil, corn oil, soybean oil, cottonseed oil.

Linoleic acid is an omega-6 fatty acid and it is the primary essential fatty acid in the diet. The body uses linoleic acid to make arachidonic acid.



Balance omega-3 and omega-6 fatty acid intake with a ratio of 1 part omega-3 to 4 parts omega-6 fatty acids.

Arachidonic acid

Pork fat, poultry fat, Meats or can be made in the body from linoleic acid.

arachidonic acid, which is the form that is used in the body for synthesis of the hormone-like compounds that are essential for blood pressure regulation, blood clot formation, blood lipid synthesis, and immune response to injury and disease.


Omega-3 Fatty Acids
Linolenic acid

Canola oil, soybeans/products made from soybeans (oil, tofu, tempeh, soyburgers), walnuts, wheat germ, margarine and shortening made from canola and soybean oil, Marine sources include fish, especially oily fish such as Atlantic salmon, mackerel, Southern blue fin tuna, trevally and sardines and butternuts.

  • Lower triglyceride levels, which are important risk factors in coronary heart disease
  • Improve blood vessel elasticity
  • Keep the heart rhythm beating normally
  • Thin the blood, which makes it less sticky and less likely to clot
  • Reduce inflammation and support the immune system
  • Reduce blood pressure
  • May play a role in preventing and treating depression
  • Contribute to the normal development of the fetal brain.
  • Linolenic acid is an omega-3 fatty acid. The body can make eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from linolenic acid



Human milk, shellfish, fish (mackerel, tuna, salmon, bluefish, mullet, sturgeon, menhaden, anchovy, herring, trout sardines), or can be made from linolenic acid.

The body can make eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from linolenic acid. EPA and DHA are important for normal growth and development in children. Without these fatty acids, children would not grow normally. EPA and DHA are also active in brain and eye development. These fatty acids may also be important in the prevention and treatment of heart disease, hypertension, arthritis, and cancer, especially in adults. EPA and DHA are also used by the body to make hormone-like compounds which are essential to many functions. They include immune response to injury and infection, blood lipid synthesis, blood clot formation and blood pressure regulation.


The ugly: trans fats (try to limit these)

Margarines (especially hard margarines)

Commercially fried foods

Bakery products made with shortening, partially hydrogenated oils and fats (including cakes, cookies, crackers, croissants, doughnuts, fried and breaded foods, muffins, pastries and other snack foods)

One McDonald's large fries contains 8 grams of trans fat.

Trans fats are actually unsaturated fats, but they can raise total and LDL (bad) cholesterol levels while also lowering HDL (good) cholesterol levels. 

In June 2006, the American Heart Association (AHA) issued its "2006 Diet and Lifestyle Recommendations." The AHA recommends that your daily intake of trans fats be limited to 1 percent of total calories, which is equivalent to roughly 2 to 2.5 grams of trans fat per day.


Proteins are polymers of amino acids linked together through a peptide bond.. The shape and thus the function of a protein is determined by the sequence of its amino acids. Digestion of proteins produces amino acids, some of which are essential to the nutritional well being of the human.

Like carbs & fats these also provide energy but due to the presence of nitrogen in their structure they perform one of the most vital functions needed for a healthy life i.e. for building up of body's cells & tissues & for repairing & maintaining the worn out tissues. It also helps in synthesis of antibodies, enzymes, & hormones.

Animal sources of proteins are of better quality are readily absorbed & utilized by the body. These include milk & milk products, eggs, meat, poultry, fish, liver & an exception is soybean, which is a plant source. Plant sources include cereals, pulses, dry fruits, nuts, beans etc.

Daily requirement of protein is 1g/kg body weight. For e.g. A normal adult man of 60kg will require 60gm of protein. However, in stage of growth or illness requirement is increased.

The Function of Protein Includes:


Vitamins are a group of protective nutrients, which aids in normal cell function, growth and development. A regular daily intake of all vitamins is needed (with the exception of a few like vitamin A, there are no appreciable stores in the body). There are two main groups:

These are required in very small amounts but are important for our growth & development. They make enzymes, which help to progress our body's chemical reactions. They should be regularly consumed as their deficiency can lead to diseases such as night blindness, scurvy, pellagra, etc.


Found in


What it does

Vitamin A
(Retinol or Beta-carotene)

Liver, egg yolk, dairy products, margarine. Beta carotene (pro-vitamin A) is found in dark green and deep yellow fruits and vegetables.

5,000 IUb

Keeps eyes healthy; develops bones; protects linings of respiratory, digestive and urinary tracts; maintains healthy skin and hair. Beta carotene fights free radicals (chemicals that damage cells).

Vitamin B1

Whole grains, cereals and enriched grain products; also legumes (dried beans, peas, and nuts), organ meats, lean pork and eggs.

1.1 - 1.5 mg

Promotes healthy functioning of the nerves, muscles and heart. Metabolizes carbohydrates.

Vitamin B2

Organ meats, enriched breads and cereals, legumes, almonds, cheese and eggs; also meat, fish and dark green vegetables.

1.3 - 1.7 mg 

Metabolizes carbohydrates, fats and proteins, produces hormones; promotes eye and skin health.

Vitamin B3

Meat, organ meats, whole grains and cereals, and legumes; also eggs, milk, green leafy vegetables and fish.

15 - 19 mg

Metabolizes carbohydrates and fats; helps functioning of digestive system; maintains health skin.

Vitamin B5
(Pantothenic Acid)

Organ meats, yeast, raw vegetables, eggs and dairy products.

4 - 7 mg suggested

Produces hormones and maintains body's immune system.

Vitamin B6

Whole-grain products, poultry, fish, and nuts; also meat, most fruits and vegetables, eggs and dairy products

1.6 - 2 mg

Metabolizes protein; helps produce hemoglobin; promotes functioning of digestive and nervous systems, and healthy skin.

Vitamin B12

Primarily organ meats; also fish, lean meats, poultry, cheese, and eggs.

2 µg

Builds genetic material of cells and produces blood cells.

Vitamin C
(Ascorbic Acid)

Almost exclusively fruits and vegetables (especially citrus fruits, tomatoes, peppers, strawberries, and cantaloupe) although breast milk and organ meats contain small amounts. 

100 - 200 mg

An antioxidant, fights and resists infection; heals wounds; promotes growth and maintenance of bones, teeth, gums, ligaments and blood vessels.

Vitamin D

For most people, sun exposure is the primary source of vitamin D. Food sources include Vitamin D-fortified milk, eggs, fish-liver oils and fatty fish such as herring, mackerel and salmon.

400 IU

Builds strong bones and teeth and maintains the nervous system.

Vitamin E

Vegetable oils, nuts, wheat germ and whole-wheat products, egg yolks and green leafy vegetables.

Women 8 mg;
Men 10 mg

Protects the lungs, nervous system, skeletal muscle and the eye's retina from damage by free radicals; may reduce risk of heart disease by protecting against atherosclerosis.

Vitamin H

Oats, organ meats, yeast and eggs (cooked); also whole-wheat products, dairy products, fish and tomatoes.

30 - 200 µg suggested

Metabolizes proteins and carbohydrates; breaks down fatty acids.

Vitamin K

Dark green leafy vegetables, eggs, cheese, pork and liver.

60 - 80 mg

Promotes normal blood-clotting.

Vitamin M
(Folic Acid)

Vegetables (especially dark-green ones), organ meats, whole-wheat products, legumes and mushrooms.

180 - 200 µg

Synthesis of protein and genetic materials; may help prevent some cancers, heart disease and stroke; when taken during pregnancy, protects against some birth defects.

These are also needed in small amounts but are important for our body's basic growth & structure. There are some 50 minerals in our body serving important functions like formation of bones & teeth, formation of blood, hair growth, nail growth, skin integrity etc. Food sources include - egg, meat, milk, cheese, nuts, vegetables, beans, banana, orange, melons, salt etc.



Major minerals





Needed for proper fluid balance, nerve transmission, and muscle contraction

Table salt, soy sauce; large amounts in processed foods; small amounts in milk, breads, vegetables, and unprocessed meats


Needed for proper fluid balance, stomach acid

Table salt, soy sauce; large amounts in processed foods; small amounts in milk, meats, breads, and vegetables


Needed for proper fluid balance, nerve transmission, and muscle contraction

Meats, milk, fresh fruits and vegetables, whole grains, legumes


Important for healthy bones and teeth; helps muscles relax and contract; important in nerve functioning, blood clotting, blood pressure regulation, immune system health

Milk and milk products; canned fish with bones (salmon, sardines); fortified tofu and fortified soy milk; greens (broccoli, mustard greens); legumes


Important for healthy bones and teeth; found in every cell; part of the system that maintains acid-base balance

Meat, fish, poultry, eggs, milk, processed foods (including soda pop)


Found in bones; needed for making protein, muscle contraction, nerve transmission, immune system health

Nuts and seeds; legumes; leafy, green vegetables; seafood; chocolate; artichokes; "hard" drinking water


Found in protein molecules

Occurs in foods as part of protein: meats, poultry, fish, eggs, milk, legumes, nuts

Trace minerals (microminerals)

The body needs trace minerals in very small amounts. Note that iron is considered to be a trace mineral, although the amount needed is somewhat more than for other microminerals.

Trace minerals





Part of a molecule (hemoglobin) found in red blood cells that carries oxygen in the body; needed for energy metabolism

Organ meats; red meats; fish; poultry; shellfish (especially clams); egg yolks; legumes; dried fruits; dark, leafy greens; iron-enriched breads and cereals; and fortified cereals


Part of many enzymes; needed for making protein and genetic material; has a function in taste perception, wound healing, normal fetal development, production of sperm, normal growth and sexual maturation, immune system health

Meats, fish, poultry, leavened whole grains, vegetables


Found in thyroid hormone, which helps regulate growth, development, and metabolism

Seafood, foods grown in iodine-rich soil, iodized salt, bread, dairy products



Meats, seafood, grains


Part of many enzymes; needed for iron metabolism

Legumes, nuts and seeds, whole grains, organ meats, drinking water


Part of many enzymes

Widespread in foods, especially plant foods


Involved in formation of bones and teeth; helps prevent tooth decay

Drinking water (either fluoridated or naturally containing fluoride), fish, and most teas


Works closely with insulin to regulate blood sugar (glucose) levels

Unrefined foods, especially liver, brewer's yeast, whole grains, nuts, cheeses


Part of some enzymes

Legumes; breads and grains; leafy greens; leafy, green vegetables; milk; liver

Other trace nutrients known to be essential in tiny amounts include nickel, silicon, vanadium, and cobalt.


Though not a food, it is an important component of our diets. It is required for our basic metabolism as serves as a medium for all chemical reactions, maintains our body's temperature, helps in nutrition processes etc. A 10% loss of water can lead to dehydration & a 20% loss may even lead to death. A daily diet is not complete without consumption of 8-10 glasses of water.

Health is often taken for granted, & its value is


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