Calculating Your Calorie Defecit

Most experts agree that you should lose weight slowly, at 1-2 lbs a week.  (Of course when you have a lot of weight to lose in the beginning, it can come off much faster than that... but that doesn't last long!)

In order to find out how many calories you should consume to lose 1-2 lbs a week, you will subtract a percentage of your total calories according to how much weight you want to lose.  Here's the numbers:

10-15 lbs loss needed- 18%
20-35 lbs loss needed- 25%
35-65 lbs loss needed- 35 %
70+ lbs loss needed- 40%

So yesterday we figured I burn about 2508 calories a day, for a 175 lb, 25 year old female.  Let's say I want to lose 30 more pounds:

2508 x .25 = 627
2508-627= 1881

So in order to lose 1-2 pounds a week, I need to eat 1881 calories a day.  That ain't too bad.  ;)

The thing to remember is that as you lose weight, you'll have to re-calculate your BMR and your needed calorie defecit.  Smaller people need less calories.  Re-calculate every 5-10 lbs or so in order to stay on track.  :)

How Many Calories You Need- Calculating Your BMR

To figure out how many calories you need in one day, you can calculate your BMR.  BMR stands for "basal metabolic rate" and is the number of calories you would burn in one day if you just laid around doing absolutely nothing.  The formula is the following:

Women: BMR= 655+ (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years)

Men: BMR= 66+ (6.23 x weight in pounds) + (12.7 x height in inches) - (6.8 x age in years)

If you aren't that good in math and want the easy calculator, LOL, you can find that HERE.

So for me, at 175 lbs, 68 inches, and 25 years old, my BMR is 1618.35.


Once you have your BMR, you add in your activity factor using the Harris Benedict Equation to figure your daily calorie expendeture.  Guess modestly on this.  People tend to think they are more active than they are.  ;)

Harris Benedict Formula

To determine your total daily calorie needs, multiply your BMR by the appropriate activity factor, as follows: If you are sedentary (little or no exercise) : Calorie-Calculation = BMR x 1.2 If you are lightly active (light exercise/sports 1-3 days/week) : Calorie-Calculation = BMR x 1.375 If you are moderatetely active (moderate exercise/sports 3-5 days/week) : Calorie-Calculation = BMR x 1.55 If you are very active (hard exercise/sports 6-7 days a week) : Calorie-Calculation = BMR x 1.725 If you are extra active (very hard exercise/sports & physical job or 2x training) : Calorie-Calculation = BMR x 1.9 So with my running 6 days a week, and weights 3 days a week, I will say I'm moderately active.  (Guessing low on this!) So we'd multiply my BMR by 1.55.  So, 1618 x 1.55= 2507.9 So I burn about 2508 calories a day.  To *lose* weight, I must eat under 2508 calories a day.  The bigger the defecit, the faster I lose! :) Tomorrow I will post on how much calorie defecit you'll need to lose a certain amount each week.  (1 lb, 2 lbs, etc)