DAILY CALORIE CONSUMPTION USING ACTIVITY LEVELS

To calculate daily calorie needs, BMR value is multiplied by a value between 1.2 and 1.9 based on the persons activity level or active metabolic rate(AMR).

Sedentary = 1.2 (little or no exercise, desk job,sitting,driving)
Lightly active = 1.375 (light exercise/sports 1-3 days/wk)
Modarately active = 1.55 (moderate exercise/sports 3-5 days/wk)
Very active = 1.725 (hard exercise/sports 6-7 days/wk)
Extra active = 1.9 (hard daily exercise/sports & physical job i.e. a full time worker)

Since we know our physical activity level we can calculate our daily calorie rate.

                                Cal/day = BMR X AMR


Using previous BMR example from Harris-Benedict equation (i.e. Women: BMR = 655 + (9.6 X wt in kg) + (1.8 X ht in cm) - (4.7 X age in years) & Men: BMR = 66 + (13.7 X wt in kg) + (5 X ht in cm) - (6.8 X age in years)).
Let the women's BMR from prevoius example be 1511 cal,


Now if the womens activity level is Sedentary (1.2)i.e. no exercise,


                              Cal/day = BMR X 1.2
                                          
                                           = 1511 X 1.2

                                           = 1813 cal/day

Since the women has no exercise, her BMR is multiplied by 1.2, which gave her Cal/day should be 1813 cal.
If the womens activity level is moderately active (i.e. 1.55), then her Cal/day would have been 2342 cal. That means her intake should be 2342 cal/day and her calorie burn per day should be 831 cal (2342 - 1511 = 831). This is to maintain the weight. To loose weight, increase your activity level or burn your excess calories than you should be burning/taken.
Similarly your cal/day can be calculated using MD Mifflin and ST St Jeor equation(P(BMR) = (9.99m + 6.25h - 4.92a + s) cal/day where s is +5 for males and -161 for female).

Since all these equations give approximately the same calorie value, calculate your cal/day value using one of the equations and keep a track on your daily calorie intake. Let us think your goal calorie intake should be 1802 but your intake is 3000 cal. Donot directly reduce your cal intake from 3000 to 1802.

This is the wrong way of loosing the weight.Reduce the intake day by day.Weight yourself after a month and adjust your diet accordingly. If you think your loosing or gaining weight too fast, increase or decrease your calorie diet acordingly.