Dietary Macronutrients – Nutritional Components of Food


Health as defined by the World Health Organization (WHO) is defined as the state of complete physical, mental, and social well-being and not merely the absence of disease and infirmity. The knowledge of food and nutrition has a direct influence in maintaining good health of an individual.

Food is a complex mixture of various substances which help to:

  • Provide sufficient energy and heat for the various activities of the body.
  • Helps in the growth, repair and maintenance of bodily tissues.
  • Helps to keep the digestive system working optimally.

Nutrition is the science of food which deals with the dynamic process in which the food is consumed and digested and then the nutrients are absorbed and distributed to bodily tissues for utilization while wastes are disposed of by the body. Nutrients are the constituents in food that must be supplied to the body in suitable amounts.

In addition, to acquire optimal health,  one must include a daily routine of consuming a balanced diet consisting of all the major food groups and vital components in appropriate quantities.

The dietary components of food are:

  • carbohydrates
  • proteins
  • fats
  • minerals
  • vitamins
  • dietary fiber
  • water

Moreover, these are broadly classified into three groups:

  1. Energy giving foods: these are composed of carbohydrates and fats, which provide us with most of the energy our bodies require.
  2. Body building foods: these are rich in proteins and are involved in growth and repair of the cells.
  3. Protective foods: these are rich in vitamins and minerals and are involved in building up the body’s immune system.

We will briefly cover why all of these components are so important along with the functions they perform.

These form the main bulk of the diet and are the chief source of energy for our bodies. They play an important role in the metabolism of fats along with forming protein structures (non-essential amino acids). Carbohydrates include sugars and starches.

  • Candy, soft drinks, sweets and desserts contain lots of simple sugars (table sugar) and are not ideal.
  • Bread, oatmeal, potatoes and rice contain starch and provide a slow release of glucose when whole wheat foods are chosen (brown rice, sweet potatoes, old-fashioned oatmeal, whole wheat bread).

In a balanced diet, 60% of our daily calorie requirement should come from carbohydrates. However, the amount can vary from 50% to 70% in each person’s diet.

These are a more concentrated source of energy than carbs and contain 9 calories per gram (versus 4 calories per gram for carbohydrates and protein). Fat is required for the absorption of vitamins A, D, E and K. Fats are important for:

  • Provide flavor and taste to food.
  • Provide cushioning support to our internal vital organs.
  • Provide essential fatty acids (EFAs) which help in reducing blood cholesterol along with promoting growth and maintaining skin integrity.

When foods include hydrogenated oils and trans fats, it means that the amount of EFAs in these products is greatly reduced and these should not be consumed on a daily basis. Healthy fats can be obtained from olive oil, fish, avocados, nuts and seeds. Nuts, seeds and fish are rich sources of EFA’s. The fat in a balanced diet should provide around 20 to 25% of the total calories in a person’s diet. However, young children can benefit from an increased amount of healthy fats in their diet.

Like carbohydrates and 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 which include building up of the body’s cells and tissues while also helping to repair and maintain them. Including fat in your diet also helps in the synthesis of antibodies, enzymes and hormones.

Animal sources of protein are readily absorbed and utilized by the body. These include milk and milk products, eggs, meat, poultry and fish. Some plant sources of protein include nuts, beans and seeds.

The daily requirement for protein is 1 gram per pound of body weight. For example, a normal adult male who weighs 200 pounds will require 200 grams of protein per day. However, in stages of growth or illness, the requirement is increased. For athletes and fitness enthusiasts, the daily protein requirement can go as high as 2 grams per pound of body weight in order to repair and rebuild muscle tissue.

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

There are fat-soluble vitamins (A, D, E and K) and water-soluble vitamins (B-complex and C). Chief sources include vegetables and fruits. Our diet should include these sources in most of the meals we eat each day.

These are also needed in small amounts but are important for our body’s basic growth and structure. There are some 50 minerals in our body serving important functions like the formation of bones, teeth, blood, hair growth, nail growth, skin integrity, etc. Excellent food sources include eggs, meats, milk, cheeses, nuts, vegetables, beans, bananas, oranges, melons, etc.

Dietary Fiber
This is a type of carbohydrate found in vegetables, fruits and whole grains. Fiber absorbs water and increases bulk of intestinal contents and helps in intestinal bowel movements. Fiber deficiency leads to constipation. Fiber also lowers cholesterol and helps in weight reduction.

Though not a food, water is a very important component of our diets. It is required for our basic metabolism as it serves as a medium for all chemical reactions, maintains our body’s temperature, helps in processing foods, etc. A 10% loss of water can lead to dehydration and a 20% loss may even lead to death. An optimal diet is not complete without consuming at least 8-10 glasses of water.

I hope this article has helped you understand the basic nutritional components of food. Health is often taken for granted and its value is not fully understood until it is lost. So, try your best to eat a nutrient dense whole food diet that is well-balanced so you can live a healthy life!

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About Author

I joined a diploma course in health nutrition and dietetics from the VLCC institute in North Africa, which is one of the brand names in the weight management industry. It is my goal to achieve success in the field of weight management and nutrition. See my profile page for more information!

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