Food security is defined as access by all people at all times to enough food for an active healthy life.Food security to individuals requires sufficient purchasing power with them so that they can acquire the food they need.For healthy life,the food available should be adequate in quality as well as quantity to meet nutritional requirement.

Two commonly used definitions of food security come from the UN's FAO and the USDA:

• Food security exists when all people, at all times, have physical, social and economic access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life.
• Food security for a household means access by all members at all times to enough food for an active, healthy life. Food security includes at a minimum (1) the ready availability of nutritionally adequate and safe foods, and (2) an assured ability to acquire acceptable foods in socially acceptable ways (that is, without resorting to emergency food supplies, scavenging, stealing, or other coping strategies).  

India can be legitimately proud of having eliminated major famines since independence,we can look back with pride and satisfaction on the revolution.One of the first efforts of the country was to build up a food security system to ensure that the threat of famine no longer stalks the country.The PDS providing food grains at affordable prices is one of the key features of the government's food security policy.To improve availability of food to people living in most vulnerable areas the revamped PDS gave priority to set up PDS in such areas.The buffer stock for the PDS is enough (in fact,in surplus) to meet an eventuality.BPL food grants are there, but because of lethargy of governments in the states in identifying BPL cases,food stocks are rotting in the godowns and the miserable poor are dying a slow death.

Food security in the different stages of development may be taken in the following way-
Stage1-Cereals only

Stage2-Cereals and pulses only

Stage3-Cereals,pulses,milk and milk products.

Stage4-Cereals,pulses,milk and milk products ,vegetables ,fruits,fish ,eggs and meant and other nutritious supplements.

The main components of the food security system is to promote domestic production to meet the demands of growing population and as also to reduce under nutrition among a large section of population and for that providing MSP for procurement and storage of food items.Operating a PDS and act as a countervailing mechanism against traders and businessmen who try to push up prices during periods of shortages of food.