A look at my personal BMR and weight loss.
My wife and I have been working out since the 2nd week of January, once she got clearance after a foot and ankle surgery late last year. For awhile, we were both making good gains but for the last 4 weeks our weight has slowly been going back up, even with an increase of working out from 4 days/week to 5 days/week. Frustrating! So, I’ve embarked on a deeper understanding of calories in vs. calories out.
The first aspect of figuring out how many calories you should be taking in is something called the BMR. BMR, or Basal Metabolic Rate, is the rate that your body burns calories throughout a 24 hour day. I am not intending to go into depth about BMR or why the formulae are different for men and women. To get into that you need to understand what a metabolism is. In simple terms, your metabolism is every hormone your body produces, and when in balance, how it burns and/or stores energy. (One of the sources I am using is the book Mastering your Metabolism by Jillian Michaels.) For now I will simplify and urge a life long habit of eating clean; meaning cut out the processed foods, high fructose corn syrup foods, endocrine inhibitors, and try to eat from local producers and/or certified organic producers.
The formulae for figuring out your BMR is simply:
- 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 year )
This, unto itself, is only half of the way to your caloric needs. To figure that out you need to figure out your activity level, or use something like a Fitbit to track your activity level. Since I’ve been logging all of my workouts for the last 8 weeks and recently purchased a Fitbit Flex, I have data I can go back over to figure out my daily caloric burn. I ended up using the Harris Benedict Formula for calculating caloric burn.
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 moderately 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
For weight loss I have discovered that 1 pound of fat is pretty much 3500 calories. If you want to lose 1 pound each week your calories in (food) should be 3500 calories lower than your total calories out (daily activity plus exercise). Since I currently weigh about 220 pounds and have a target weight of 195 pounds I channeled the inner engineer in me and came up with the following chart:
Now, looking back for the last several weeks through my tracking of calories burned I am averaging 2,400 on a non-workout day and 3,150 on a workout day. So, my average week is pretty close to (2 x 2400) + (5 x 3150) or 20,550 calories burned each week. If I wanted to maintain my weight I would need to eat this many calories every week. If I wanted to lose 2 pounds a week, I would need to eat 7,000 calories less than this each week. And for me, I believe it needs to be consistent each day, not 3,000 calories in today and 1,000 calories in tomorrow. And having lived the sedentary lifestyle for so many years, I can say with absolute certainty that exercise is required to lose weight. And please note on my chart (left chart) where I ended up while currently weighing 220 pounds. Between lightly and moderately active! But doesn’t it say if you work out 3-5 times a week you are moderately active? Yes, as a (very) general rule. But everybody (and every body) is different.
Now, why did I do all of this math stuff? I did it because following an software application’s advice I was not losing weight! And I wanted to figure out why. When punching all of this into MyFitnessPal and Fitbit it was recommended that I should be eating just aver 1,400 calories a day. Well, that is a lot lower than 2,000 calories a day that I just figured out I should be eating to lose weight. That means I should be losing weight even faster, right? From everything I’ve researched, the answer is not only no, but hell no! Not enough calories will force the body into a different state and it will hold on to every calorie it can. Starvation mode over time does not work. In fact, it is highly suggested that you don’t have a deficit of more than 20% of your maintenance level unless you are obese. Then, maybe 30% might be good to start. The right hand part of the chart (above) is a 20% reduction in calories. Half way between 15,523 and 17,499 is about 16,500 calories a week. This is a 4,000 calorie deficit each week which would equate to about 1.1 pounds lost each week. 16,500 divided by 7 days would put me right around 2,357 calories each day to eat.
Well holy hand grenades of Antioch! That is nearly a 1,000 calories more than both MyFitnessPal and Fitbit put me at! Does that explain why for the last 3 weeks I’ve been getting more and more sore, more and more tired, rundown and worn out? Maybe. For the next 3-4 weeks I will be working on an input of about 2,300 calories a day instead of 1,400 a day and see if things start changing.