A balanced diet is one which provides all the nutrients in required amounts and proper proportions.It can easily be achieved through a blend of the basic food groups. The Quantities of foods needed to meet the nutrient requirements vary with age,gender,physiological status and physical activity.
Nutrients that we obtain through food have vital effects on physical growth and development,maintenance of normal body function, physical activity and health.Nutritious food is, thus needed to sustain life and activity.Our diet must provide all essential nutrients in the required amounts. Requirements of essential nutrients vary with age,gender,physiological status and physical activity. Dietary intakes lower or higher than the body requirement scan lead to under nutrition(deficiency diseases) or over nutrition (diseases of affluence) respectively.Eating too little food during certain significant periods of life such as infancy, childhood, adolescence, pregnancy and lactation and eating too much at any age can lead to harmful consequences.An adequate diet, providing all nutrients, is needed throughout our lives.The nutrients must be obtained through a judicious choice and combination of a variety of foodstuffs from different food groups.
Carbohydrates, fats and proteins are macro nutrients, which are needed in large amounts. Vitamins and minerals constitute the micro nutrients and are required in small amounts. These nutrients are necessary for physiological and biochemical processes by which the human body acquires, assimilates and utilizes food to maintain health and activity.
Requirements are the quantities odd nutrients that healthy individuals must obtain from food to meet their physiological needs. The recommended dietary allowances (RD As) are estimates of nutrients to be consumed daily to ensure the requirements of all individuals in a given population. The recommended level depends upon the bio availability of nutrients from a given diet. The term bio availability indicates what is absorbed and utilized by the body. In addition,RDA includes a margin of safety, to cover variation between individuals, dietary traditions and practices.
The RD as are suggested for physiological groups such as infants, per-schoolers, children, adolescents, pregnant women, lactating mothers, and adult men and women, taking into account their physical activity. In fact, RD As are suggested averages/day. However, in practice, fluctuations in intake may occur depending on the food availability and demands of the body. But, the average requirements need to be satisfied over a period of time.