Energy | Nutrition

[1st Semester Nutrition | UNIT 2 BHM116 | IHM Notes]

Food is digested, the complex nutrients i.e., carbohydrates, fats, protein are broken down into monosaccharides, fatty acids & glycerol, & amino acids, respectively. These simple forms are absorbed into the blood stream & supplied to the millions of cells in the body to be oxidized by series of complex steps to released energy.

Human being needs energy for the following:

• Basal metabolism

• Metabolic responses to food – thermo genesis / SDA

• Physical activities

• Growth

• For mothers in special conditions (pregnancy & lactation)

TEE = BMR (45 – 75percent) + Thermo genesis (10 percent) + Physical activities (15 – 50 percent)

Factors affecting the BMR

BMR is the largest component of the daily energy demand representing 45 – 70 percent of daily total energy expenditure. It is highly variable & the cause of this variation include factors such as

• body size & composition,

• age,

• gender,

• environmental condition,

• hormonal status,

• fever/illness/infection / injury,

• specific body conditions of mothers (pregnancy & lactation),

• other factors etc

Thermal effect of food (SDA)

Thermal effect of food (TEF) determined primarily by the amount of composition of food consumed. For example, is greater after consumption of carbohydrate & protein than after fat. It varies from 5-10 percent for carbohydrates, 0-5 percent for Fat, & 20 -30 percent for protein.

Physical Activity

Sedentary workers –persons taking, reading, watching TV, listening Radio, doing computer works specially sitting activities (teachers, office workers).

Moderate workers – with some activity’s servants, house cleaners, rural women, students etc.

Heavy workers – Labour class.

Energy requirement

The amount of food needed to ensure good health will vary from one individual to another. All people do not require the same amount of nutrients. Requirement vary depending upon age, gender, body size, activities, state of health etc. ICMR has prepared Recommended Dietary Allowances (RDA) for Indians.

Energy balance: Energy output – Energy input

Energy balance is a condition in which the energy provided by food is nearly equal to energy expenditure by the body resulting in a steady body weight.

Overweight & underweight both are the abnormalities

Both measured by BMI (body Mass Index)

BMI = Weight in kilograms / height in meters²

W/H²