Tag Archives: Body mass index

I’m Overweight.

Dr. C

Or at least you would think so if you looked at my body mass index (BMI). I have written about the very imperfect science of the BMI scale before here on my blog, but I thought it deserved to be revisited. BMI is basically a height to weight ratio that comes up with a number designed to make it easy for clinicians to decide if a person is overweight or obese. Before the BMI scale was invented it was hard to assess someone’s weight and say that it was appropriate because height is also an important factor in weight. BMI combined those two.

Calculating BMI is relatively simple. You need your weight in pounds and your height in inches. Take your weight and multiply it by 703. Take your height and multiply it by itself (height squared). Now divide the first number by the second number and you have your BMI. To see my calculations or do your own click this link. My BMI falls in the “overweight category” with a score of 26.2. However, my body fat percentage is about 18%. This is well within the acceptable range for a 33-year-old man. (And I clearly do not look overweight!)

BMI misses many things when calculating whether someone is at the proper weight.

The problem for some people, like athletes, it does not take into account muscle mass. A person that is heavily muscled will always be overweight according to the BMI. As a matter of fact, I have been considered “overweight” since college despite always being is relatively good shape. If we look at professional level athletes, most of them would be considered obese!

I understand that not everyone is an elite athlete. What about the elderly? BMI is not ideal for them either. In the United States that equates to about 43 million people. Many times an elderly person will fit nicely into the BMI by being considered “ideal weight” for their height. This can be significantly misleading. Why? In the elderly muscle mass begins to drop. It happens to all of us. However, with this drop in muscle mass comes a drop in weight. As weight is lost a person is likely to fall into the “ideal weight” category even though they should be concerned about muscle mass loss. This loss in muscle mass causes a loss in strength and stability, increasing the risk of falls and increasing the risk of osteoporosis. Another problem with muscle loss is the change in your body composition. As muscle mass is lost one’s body fat percentage increases. Body fat percentage is a great indicator of health. The lower it is (within reason) the healthier you are, generally speaking.

BMI also fails to take into account many other health factors like diet, exercise, inflammatory markers, nutrient status, stress load, chemical exposure, social well-being, mood stability, and a whole host of other things we know have a large impact on our health. However, it is still widely used as a primary assessment of one’s health. As I said, it’s an imperfect science. In my opinion, it’s so imperfect it should be eliminated.

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35 Points From A Body Transformation Contest

Recently, I entered into a 6-week body transformation challenge at the gym I belong to. It’s called KDR Fitness. Great place. It began February 10th and ended March 22nd. It was technically 41 days long. I decided to enter because I needed a kick in the butt to get back to the gym. In the previous year gym days were hard to come by. With a brand new baby and practice, my gym time was way down. To top it off, I had a neck injury that took me completely out of the gym for 3 months at the end of the year. As a consequence my body fat had increased to 21.7%. Not ideal for me. During the contest, I recorded my diet and exercised in order to lose body fat and gain lean mass. I wore a heart rate monitor for all of my workouts to calculate my calories burned and generally keep track of my workouts. Here are the things I learned:

  1. I started at 21.7% body fat.
  2. By the 4th week I was down to 19.4%
  3. By the end of the 6th week, I was down to 18.4%
  4. I gained 3.7 pounds of muscle in 6 weeks.
  5. I lost 7 pounds of fat in 6 weeks.
  6. I missed the gym.
  7. I worked out 25 times in 41 days.
  8. That’s 4 workouts per week with an occasional 5th thrown in.
  9. I ate MORE food than I had been eating and was able to lose fat and gain muscle.
  10. I burned 15,655 calories in 25 workouts.
  11. Each workout was about 1 hour.
  12. Each workout burned an average of 626.2 calories.
  13. The range of calories burned was 273 all the way up to 958.
  14. It is not that hard for me to avoid grain.
  15. I can count on one hand how many times I ate grain in 41 days (and it’s less than the whole hand).
  16. Cheat meals are important.
  17. This was a typical day in terms of food intake:
    Wake Up: 6:15
    Food for the day:
    Breakfast: 6:45 – 3 eggs, mixed veggies, and cheese cooked in butter. Coffee with organic half and half.
    Snack: 10:15 – 3 large beef and veggie meatballs, carrots, celery, and hummus.
    Lunch: 12:20 – Chicken breast, mixed peppers, 1 whole avocado.
    Snack: 3:30 – Protein shake, steamed broccoli.
    Workout – 60 minutes – protein/carbohydrate workout drink
    Dinner: 6:45 – Meatloaf, steamed broccoli and cauliflower with olive oil.
    Snack: 9:15 – Greek yogurt and banana.
  18. Food preparation is key.
  19. Eating 6 times per day isn’t that hard IF you’re prepared.
  20. Eating a lot of vegetables is fairly easy IF you’re prepared.
  21. You don’t necessarily have to count calories if the quality of your food is good.
  22. You can eat A LOT of food if you are working out hard and still lose weight.
  23. Burpees get easier the more you do them.
  24. Working out more consistently makes you want to workout more consistently.
  25. Using the scale to measure your progress is a bad idea.
  26. My weight changed from 190.9 to 187.6 in 6 weeks. Hardly encouraging if you’re just looking at the scale.
  27. Body fat analysis is far more informative.
  28. You only have time for the gym if you make time for the gym.
  29. You don’t need to be in the gym 7 days/week.
  30. Two busy people (my wife and I) can each take turns working out during the week and get great results.
  31. You should be willing and able to do an extra workout or two from home if you need to.
  32. You can turn snow blowing and shoveling your driveway into a workout quite easily.
  33. Body mass index (a measure of height to weight) is a terrible health assessment tool. According to it, I am “overweight.” This is because my lean mass is high, not because I am actually overweight.
  34. My basal metabolic rate (calories I burn at rest over 24 hours) increased from 1,835 to 1,870 over six weeks.
  35. The area of my body that gained the most muscle (as percent growth) was my left arm.

I was on a team of three and our entire team (Bro’s before Hoho’s) did very well. The winning team will win $3,000. I’ll find out in a couple of days which of the 18 teams won the contest. That’s not the important part, but it sure would be nice!

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Body Mass Index – Don’t pay any attention to it

The Body Mass Index, or BMI,  is used to ascertain whether someone is overweight, obese or at the correct weight for their height.  It’s used by health professionals across this country as a guide for their patient’s health.  It’s wrong.

The reason for this blog is a conversation I had with a good friend of mine.  He also happens to own a gym and is a very talented and knowledgeable trainer/fitness coach.  We were discussing it in relation to his clients and my patients and how people are often times misled by the numbers they see when they use the BMI scale.

BMI was designed to be used as an easy tool for clinicians to assess their patients in terms of body weight relative to height. Before the BMI scale was invented it was hard to assess someone’s weight and say that it was appropriate because height is also an important factor in weight.  BMI combined those two.

How to calculate BMI:

The formula is simple.  You need your weight in pounds and your height in inches.  Take your weight and multiply it by 703.  Take your height and multiply it by itself (height squared).  Now divide the first number by the second number and you have your BMI.  Here is an example.  We’ll use my numbers.  I am 201 pounds and 71 inches tall.

201 lbs x 703 = 141,303
71 in. x 71 in. = 5,041
141,303/5,041 = 28.03

So my BMI is just over 28.  This puts me in the overweight category, actually moving close to obesity.  Wait…what?

If you look below you can see the classification system used for BMI.

You will see that anything above 30 is considered obese.  Technically anything above 29.9 is obese.  If we use this scale, I am only 13-14 pounds short of being considered obese.  People who know me will tell you that I do not look obese.  They will also tell you that I do not even look overweight.  So what’s the catch?

That is the problem with using BMI to assess health.  It doesn’t take into account many factors.

The problem for some people, like athletes, it does not take into account muscle mass.  A person that is heavily muscled will always be overweight according to the BMI.  As a matter of fact, I have been considered “overweight” since college despite always being is relatively good shape.  If we look at professional level athletes, most of them would be considered obese!

I understand that not everyone is an elite athlete.  What about the elderly?  BMI is not ideal for them either.  Many times an elderly person will fit nicely into the BMI by being considered “ideal weight” for their height.  This can be significantly misleading.  Why?  In the elderly muscle mass begins to drop.  It happens to all of us.  However, with this drop in muscle mass comes a drop in weight.  As weight is lost a person is likely to fall into the “ideal weight” category even though they should be concerned about muscle mass loss.  This loss in muscle mass causes a loss in strength and stability increasing the risk of falls and increasing the risk of osteoporosis.  Another problem with muscle loss is the change in your body composition.  As muscle mass is lost one’s body fat percentage increases.  Body fat percentage is a great indicator of health.  The lower it is (within reason) the healthier you are, generally speaking.

So does it work for anyone?  Yes, there are some people that it works for.  If a person is sedentary and eats a poor diet it may accurately depict your current weight status (ideal, overweight or obese).  There are, however, better ways to assess health.

Then how do I know if my weight is appropriate?

The best way to assess your weight status is to perform body composition.  This gives us a percentage number based on body fat.  For example, if you weigh 200 lbs and 50lbs of that is from fat, your body fat is 25%.  Below is the ideal body fat percentages for men and women.

The gold standard for measuring it is the caliper test or skin fold test.  A pinch of skin is precisely measured by calipers at several standardized points on the body to determine the subcutaneous fat layer thickness. These measurements are converted to an estimated body fat percentage by an equation.  It is most reliable when taken over time and it must be done by the same person to be accurate.  Techniques can vary from person to person and may change the results.

The other way to measure it by bioelectrical impedance.  You are hooked up to electrodes that are spaced far apart on your body; usually on each hand or on a hand and a foot.  An electrical signal is passed between the electrodes and the resistance to the current flow is measured.  This is a painless process.  Fat and muscle have different resistance rates so the machine can estimate the body fat percentage based on that.  It is affected by hydration levels so be sure to be hydrated when you take a test like this.  This is a very accurate method and does not depend on a person’s technique as the skin fold test does.

The best way to get your body fat to the desired level is a healthy diet and exercise.  You want to increase muscle mass and decrease fat.  This is done by weight training and short duration, intense circuit type workouts.  All of this can easily be done at any local gym.

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