Nutrition - The process of providing or obtaining the food necessary for health and growth.
Or
Science of food and it's relationship to health is called nutrition.
Nutrients- are substances that are not synthesised in body in sufficient amount and hence need to obtained through diet.
The required amount of nutrient vary depending upon the age of the person ,sex , weight,or physical activity .
Types of Nutrients
1) Macronutrients
2) Micronutrients
1) Macronutrients - required in a large amount helps in the energy requirement.
- maintain the body structure.
For example - carbohydrate ,lipids and protein substance and hence need to be taken in a large quantities.
2) Micronutrients - required in small amount helps in various generating process and reaction.
Eg- vitamins, electrolyte , minerals.
Calorific value of food
It is amount of heat energy generated by burning 1gm of food completely in the presence of 02.
The calorific value of food can be measured experimentally in apparatus called bomb calorimeter.
Nutrient calorific value in Cal/g
Carbohydrate. 4
Lipids. 9
Proteins. 4
Energy expenditure in human
Energy expenditure in human is attributed to the flowing process that occur in the body.
1) BMR ( Basal metabolic rate)
2) SDA ( specific dynamic Action)
3) Physical Activity
