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,
Lori
Hi Lori:
Thank you for the tips. In response to your questions I have a very busy life style so I have to do whatever I can fit in to my schedule for example: On football practices days I will walk the track – 3miles in 50 minutes. On football game days I add in 45 minutes at the gym 20 minutes on the elipitical machine for cardio. 15 minutes of weight lifting (only one body part 15 reps 3 times) 100 situps, then strecthing. Yesterday I was not able to do either so I jumped roped about 5 minutes and 25 minutes on a video then 100 sit-ups. I plan to exercise 6 days a week. I have never calculated my caloric intake. With the tips you have given me I am going to begin and will update you next time.
Comment by Jacqueline — September 13, 2007 @ 1:14 pm |
Wow! Jacqueline you are an inspiration. I think you have the right approach to use whatever available time you have to exercise. Too often we feel if we can’t get to the gym then we can’t exercise. There’s no reason why we can’t break up our workout into smaller chunks of time, and there are certainly things we can do at home or in a hotel room.
Comment by lpthreatt — September 13, 2007 @ 5:14 pm |
It seems like a really helpful tool, but I don’t think there’s any consideration given to the individual’s ratio of lean mass to adipose tissue. Unless I completely missed something.
Comment by Krispy — June 26, 2008 @ 3:43 pm |
Thank you! Ive been an athlete from age 6 through my final year playing collegiate soccer, but have stopped due to a few major injuries and 2 surgeries. Now, a few years later im trying to get back my muscle andd loose the fat I took on a long the way. Your site here has given me great information! The more I know about my body, the more I care, and inspired to take care of it! I appreciate the help I received here. It is one of my many stops on my journey. Get healthy, Feel healthy, Stay healthy!
Comment by NJ XC PWN — August 22, 2008 @ 1:27 am |
Doesn’t this have to be refigured over and over again? If it is based on your weight, and that continues to go down you will not be burning as many calories each week without increasing your workout or lowering your food intake. Just a thought.
Comment by Lauren — August 27, 2008 @ 12:17 pm |
Good calculator but it doesnt take in consideration your percentage of body fat, also for those of you looking at this thinking your going to cut out one thousand calories a day, think again. When you deprive your body of massive amounts of calories you will lose weight but the momment you start to consume a normal amount of calories(say going from 1000 cal. a day back to 2000 cal. a day) your body will start storing excess. Cut at most five hundred if your a big fellow and follow an excersize program. This will help speed your metabolic rate and increase calories burned in a day. Also stick to high protein, high fiber, low fat foods. This ensures your body has something to work with. Remember, if your body is burning sugar, your not burning fat, so put down the candy bar.
Comment by Michael Bowers — August 28, 2008 @ 10:55 pm |
Thanks! I’m always wondering the exact scientfic way to do this. I don’t like guessing and fad diets. I just count my calories! But I have a difficult time figuring out how many I burn a day. Thanks
Comment by Elaina — January 7, 2009 @ 6:43 pm |