Knowing your basal metabolic rate (BMR) is the key to knowing how many calories you should, or shouldn’t eat in a day. Simply put, your BMR is the minimum amount of calories your body requires on a daily basis to complete its basic functions (i.e. breathing, sleeping keeping your heart beating or regulating your internal temperature). Your BMR is dependent upon your age, height, and weight and gender. If you’ve noticed that every year, it becomes harder to eat whatever you want and stay slim, then, you may have discovered that your BMR decreases as you age. The good news is that a regular routine of cardiovascular exercise (walking, jogging, swimming, aerobics, etc) can increase your BMR.
Once you know your BMR, then you can determine your Total Daily Caloric Expenditure by adding to that number, the number of calories used (i.e. energy burned) in your physical activity and the energy burned in digesting your food … yes digesting your food is work and uses caloric energy.
Once you have estimated your total daily caloric expenditure, you can more accurately calculate how many calories you can afford to eat (i.e. your daily calorie budget) and how much exercise you need to do every day to maintain, gain or lose weight to meet your healthy weight goals.
Basic Daily Caloric Expenditure Calculation
1 – Estimating your BMR
Calculating your BMR can be a very scientific process, but here is a quick “back of the envelope” sort of calculation which gives a good estimate.
BMR = your body weight (in pounds) multiplied by 10.
Example: 186 pounds x 10 calories/pound = 1,860 calories
Another more accurate way of calculating your BMR is called the Harris-Benedict Formula This formula takes into consideration your gender and age along with your weight. Visit http://en.wikipedia.org/wiki/Basal_metabolic_rate for the formula.
Alternatively, you can visit this site for an online BMR Calculator that takes your age, weight and gender into account. http://www.bmi-calculator.net/bmr-calculator/
2. Next factor in Calories Used in Physical Activity
Multiply your BMR by the appropriate activity level factor, as follows:
Physical Activity Calories = (BMR x Activity Level):
- Sedentary: 20% (Sitting most of the day)
- Lightly Active: 37.5% (Walking here and there; daily chores)
- Moderately Active: 40% (Constantly moving around; daily exercise)
- Very Active: 50% (Heavy exercise for prolonged periods of time, such as training for a sport)
Example: 1,860 calories x 0.20 = 372 calories for a sedentary person.
3 – Next Factor in The Calories Used During Digestion
Calories used during digestion, are estimated at 10% for the general population..
Digestion Calories = (BMR + activity level ) x 10%:
Example: (1860 + 372 calories) x 0.10 = 223 calories
4. Total Daily Caloric Expenditure = (BMR Calories + Physical Activity Calories + Digestion Calories)
Therefore, in order to maintain my current weight I burn an average of 2,455 calories every day to support my body’s most basic needs, activity level and digestion of food.
Now that I know my daily caloric expenditure, I can figure out how many calories I need to reduce in my diet in order to reach my weight loss goal.
Keep in mind that one pound of fat is equal to 3,500 calories. Therefore as a general rule of thumb, to loose 1 pound per week, I must take in a negative 500 calories a day or negative 3,500 calories per week. I can reduce the calories by a combination of eating less and exercising more to lose weight. So you see it’s pretty simple, if the total number of calories burned is more then the calories consumed it will lead to weight loss.
My goal is to lose 30 pounds over the next 6 months; that’s approximately 1.15 pounds (4,025 calories) of fat in per week or 575 fewer calories each day. My plan is to eat 375 fewer calories and maintain a daily exercise routine that will burn up 200 calories per day.
So I’m off to the gym to find out what how long I need to exercise on the elliptical to burn at least 200 calories . I’ll let you know how things go.
My question for you:
What exercises do you do? How frequently do you do them? How many calories do you burn while exercising? Okay that’s 3 questions but you must admit they are all closely related.
Talk with you soon,