What is Food :

Food can be defined as anything solid or liquid which when swallowed,digested & assimilated in the body,helps to keep the body in a state of health.
Foods after ingestion,digestion & absorption,is utilized by the body for proper functioning.It provides the nutrients which helps us to maintain our health.
The chemical substances present in food which perform different functions relating to body growth & development & maintenance of good health are nothing but Nutrients.It gives immunity to fight diseases,maintenance of body strength & mental fitness for the performance of variety of functions throughout our life.Blood serves as the medium of transfer for these nutrients.
Nutrients are classified into the following types :
1) Proteins 2) Fats (Lipids) 3) Minerals 4) Carbohydrates 5) Vitamins 6) Fibre 7) Water.

Balanced Diet :

A balanced diet is defined as one which contains different types of foods in such quantities & proportions that the need for  & other nutrients is adequately met.
To get adequate nutrition from diet, we should consume the majority of daily calories in :
1) Fresh fruits & vegetables 2) Legumes 3) Whole grains 4) Nuts 5) Lean proteins

What is Health :

A state of complete physical,mental & social well being & not merely the absence of disease or infirmity is termed as Health.
Malnutrition: Malnutrition is commonly considered as inadequate nutrition.It can be both over-nutrition & under-nutrition.Both impose serious threats to health & life when ignored.Numerous health complications are caused due to Malnutrition.This also suggests that many disorders & diseases can be prevented if we consume foods wisely.
Optimum Nutrition : The term “Optimum Nutrition” can be defined as eating right amounts of nutrients on a proper schedule to achieve best performance & the longest possible lifetime in good health,assuming that external negative influences like accidents & infectious diseases can be avoided.The demand of body changes from minute-to-minute based on physical activity,& because medical science does not yet have a definite set of comprehensive nutritional requirements for every human genetic variation.