HARRIS BENEDICT EQUATION:

Harris benedict equation is a formula used to calculate the total calorie requirements or TEE ( total energy expenditure) of the body.
daily calorie calculations

The total calorie requirement of the body depends on three factors:
  1. Resting metabolic rate(60%)
  2. Physical activity level(30%)
  3. Thermic effect of food or specific dynamic action of food(10%)
overall these all factors leads to the total energy expenditure and requirement of the body.
The formula to calculate TEE is:
TEE= RMR + SDA + Physical activity

PHYICAL ACTIVITY:

It is the total amount of energy burned throughout the day. In overall, it accounts for about 30% of the energy requirement of the body. but if a person are highly active than it will burn more calories and in turn their calorie requirements will also increase.

THERMIC EFFECT OF FOOD:

It is the amount of calories required for the digestion of food. and food after digestion produces specific amount of energy depending on the type of food digesting.
  • Protein digestion produces about 30% of energy.
  • Carbohydrates ranges about 20-30% of energy.
  • Fats produces 5-0% of the total calories to the body.
This is the reason that protein digestion increases your body temperature.

RESTING METABOLIC RATE:

It is the amount of energy required for the proper functioning of body systems like circulatory system, respiratory system and digestive system etc at rest. RMR accounts for about 60% of calorie requirements of the body. 

HOW TO CALCULATE CALORIE INTAKE:

The steps to calculate calorie intakes are:
  1. Calculate RMR
  2. RMR + Physical Activity
  3. Physical Activity + Thermic Effect Of Food
  4. Determine Calorie Intake

1.RMR with the help of Harris Benedict Equation:

There are different methods through which RMR can be calculated through direct and indirect methods. one of these method is Harris Benedict Equation. it is different for both males and females which is given below:
MALES: 66 + (5(Height)) + (13.8(weight)) - (6.8(age))
FEMALES: 655+ (1.8(height)) + (9.6(weight)) - (4.7(age))

As some persons have a very speed RMR and some has a slow RMR. There are many factors which effect the RMR of a person:
BMI, Age, Climate, Sex, Sleep, Starvation, Exercise, Fever and Thyroid Hormones and many more.
Put height in cm, weight in kilograms and age in years.
The RMR are calculated in kilocalories.
LETS CALCULATE THE RMR OF AN ANERAGE MAN WHOES HEIGHT IS 5 FEET 9 INCHES AND WEIGHT IS 90KG ANG AGE IS 30.
SOL:
Conversion of weight into cm
5'9 = 5(12) =60 + 9 = 69(2.54) = 176
Putting these values in the equation
Males: 66+(5(height))+(13.8(weight))-6.8(age))
          =66+(5(176))+(13.8(90))-(30))
          =2000
RMR= 2000 kilocalories
FOR AN AVERAGE WOMEN IT IS 1550. 
SO THE AVERAGE CALORIE REQUIREMENT FOR AN AVERAGE MEN IS 2000 AND AN AVERAGE WOMEN ARE 1550 LEAVING A SEDENTARY LIFE STYLE.

2.RMR + PHYSICAL ACTIVITY:

FOR A LIGHTLY ACTIVE PERSON PHYSICAL ACTIVITY RATIO WILL BE 1.6 FOR MALE AND 1.5 FOR FEMALES.
FOR A MODERPERSON PH WILL BE 1.7 FOR MALES AND 1.6 FOR FEMALES.
FOR A HIGHLY ACTIVE PERSON PH WILL BE 1.9 FOR FEMALES AND 2.1 FOR MALES.
SO FOR AN AVERAGE PERSON HAVING A MODERATE PHYSICAL ACTIVITY IT WILL BE
MALES: 2000(1.7)= 3400
FEMALEA: 1550(1.6)= 2480.

3. ADD THESE VALUES WITH THERMIC EFFECT OF FOOD:

FOR MALES: 3400+340= 3740
FOR FEMALES:2480+248=2728
THIS IS THE DAILY CALORIC NEED FOR AN AVERAGE MALE AND FEMALE OF WEIGHT 30KG.
BASED ON AN AVERAGE 30 YEARS OLD PERSON WHO ARE MODERATELY THE CALCULATIONS OF THEIR MEAL PATTERENS PER MEAL AND PER DAY WILL BE:

CARBOHYDRATES:

MALE= 3740(60)=2244 CALORIES 
AND PER CARBS PROVIDE 4 KILOCALORIES SO DIVIDE THESE CALORIES WITH FOUR WE GET
2244/4= 561GRAMS 
DIVIDING THESE GRAMS INTO FOUR MEALS OF A DAY 
561/4=140 GRAMS PER MEAL.
SO A MODERATE MAN CONSUMES 140 GRAMS OF CARBOHYDRATES PERR MEAL OF A DAY.
WOMEN:2728(60)=1636CALORIES/4=409GRAMS/4=100 GRAMS.
SO AN AVERAGE WOMEN CONSUMES 100 GRAMS OF CARBOHYDRATES PER MEAL OF THE DAY.

PROTEINS:

MALE=3740(10)=374CALORIES
AND PER GRAM PROTEINS PROVIDE 4 KILO CALORIES
374/4=94GRAMS
DIVIDING THIS WITH 4 WE GET THE 4 MEALS OF DAY OF AN AVERAGE PERSON
94/4=23.5GRAMS PER MEAL.
SO AN AVERAGE MEN COSUMES 23.5 GRAMS OF PROTEINS PER MEAL OF A DAY.
WOMEN=2728(10)=273CALORIES/4=68 GRAMS/4=17 GRAMS PER 4 MEALS OF THE DAY.

FATS:

MALE= 3740(30)=1122 CALORIES 
AND PER GRAMS OF FATS PROVIDES 9KILO CALORIES SO DIVIDING THE ANSWER WITH 9 WE GET
1122/9=125 GRAMS
DIVIDING THIS WITH 4 MEALS OF A DAY WE GET THE CONSUMPTION OF FATS IN PER MEAL
125/4=31 GRAMS PER MEAL OF A DAY
SO AN AVERAGE PERSON CONSUMES 31 GRAMS OF FATS PER MEALS OF A DAY.
WOMEN=2728(30)=818.4/9=91GRAMS/4=23 GRAMS PER MEAL OF A DAY.
AS THESE ARE THE MACRO NUTRIENTS WHICH OUR BODY NEEDS FOR ITS PROPER FUNTIONING INADEQUATE CONSUMPTION OF THESE NUTRIENTS WILL LEFT OUR BODY MAL NOURISHED. BASICALLY, IF A PERSON MAINTAINS ITS CALORIES IN AND CALORIES OUT THAN THERE WILL BE NO ANY ADVERSE EFFECT IN OUR BODY AND IT REMAINS IN A BALANCE STATE.