The Body Mass Index (BMI) System Explained

 

 


Obese 3

The most commonly utilized definition includes the Body Mass Index (BMI) measurement. We doctors often need a quantitative way to describe something, so the BMI system was created for this purpose.

BMI sounds technical, but it is simply a modified ratio of your body weight and your height. With the help of a chart, you can easily determine your own BMI. For those who like knowing the finer details, the actual number is simply your body weight (in kilograms) divided by the square of your height (in meters). Don’t worry, I go through this with you.

What is your BMI?

I have included here two BMI charts. The first one is the traditional BMI chart, in the standard kilogram and meter designations. (For those of you reading this who live outside of the US, this is likely that chart that will be easiest for you). The second chart is in pounds and feet. For Americans, this will be the chart to use. You simply locate your height along the top part of the chart, then move down that column until you find your current weight. The number printed in this box will be ‘your’ BMI.

Below is a standard Body Mass Index (BMI) chart. The chart was classically created using metric measurements. Your height is measured in meters across the top and your weight is measured in kilograms along the side. For most of the world, except for the USA, this is the preferred version of the BMI chart.

Height (m)
Weight (kg) 1.45 1.5 1.55 1.6 1.65 1.7 1.75 1.8 1.85 1.9
70 33 31 29 27 26 24 23 22 20 19
75 36 33 31 29 28 26 24 23 22 21
80 38 36 33 31 29 28 26 25 23 22
85 40 38 35 33 31 29 28 26 25 24
90 43 40 37 35 33 31 29 28 26 25
95 45 42 40 37 35 33 31 29 28 26
100 48 44 42 39 37 35 33 31 29 28
105 50 47 44 41 39 36 34 32 31 29
110 52 49 46 43 40 38 36 34 32 30
115 55 51 48 45 42 40 38 35 34 32
120 57 53 50 47 44 42 39 37 35 33
125 59 56 52 49 46 43 41 39 37 35
130 62 58 54 51 48 45 42 40 38 36
135 64 60 56 53 50 47 44 42 39 37
140 67 62 58 55 51 48 46 43 41 39
145 69 64 60 57 53 50 47 45 42 40
150 71 67 62 59 55 52 49 46 44 42
155 74 69 65 61 57 54 51 48 45 43
160 76 71 67 63 59 55 52 49 47 44
165 78 73 69 64 61 57 54 51 48 46
170 81 76 71 66 62 59 56 52 50 47
175 83 78 73 68 64 61 57 54 51 48
180 86 80 75 70 66 62 59 56 53 50
185 88 82 77 72 68 64 60 57 54 51
190 90 84 79 74 70 66 62 59 56 53
195 93 87 81 76 72 67 64 60 57 54
200 95 89 83 78 73 69 65 62 58 55
205 98 91 85 80 75 71 67 63 60 57
210 100 93 87 82 77 73 69 65 61 58

For the non-metric-friendly, here is a simple chart to determine your BMI. Simply find your height column across the top, then go down to your proper weight. The number in the box where your column and row intersect is your BMI.

Height (ft)
Weight (lbs) 4’9” 4’11” 5’1” 5’3” 5’5” 5’7” 5’9” 5’11” 6’1” 6’3”
154 33 31 29 27 26 24 23 22 20 19
165 36 33 31 29 28 26 24 23 22 21
176 38 36 33 31 29 28 26 25 23 22
187 40 38 35 33 31 29 28 26 25 24
198 43 40 37 35 33 31 29 28 26 25
209 45 42 40 37 35 33 31 29 28 26
220 48 44 42 39 37 35 33 31 29 28
231 50 47 44 41 39 36 34 32 31 29
243 52 49 46 43 40 38 36 34 32 30
254 55 51 48 45 42 40 38 35 34 32
265 57 53 50 47 44 42 39 37 35 33
276 59 56 52 49 46 43 41 39 37 35
287 62 58 54 51 48 45 42 40 38 36
298 64 60 56 53 50 47 44 42 39 37
309 67 62 58 55 51 48 46 43 41 39
320 69 64 60 57 53 50 47 45 42 40
331 71 67 62 59 55 52 49 46 44 42
342 74 69 65 61 57 54 51 48 45 43
353 76 71 67 63 59 55 52 49 47 44
364 78 73 69 64 61 57 54 51 48 46
375 81 76 71 66 62 59 56 52 50 47
386 83 78 73 68 64 61 57 54 51 48
397 86 80 75 70 66 62 59 56 53 50
408 88 82 77 72 68 64 60 57 54 51
419 90 84 79 74 70 66 62 59 56 53
430 93 87 81 76 72 67 64 60 57 54
441 95 89 83 78 73 69 65 62 58 55
452 98 91 85 80 75 71 67 63 60 57
463 100 93 87 82 77 73 69 65 61 58


Of course, if we were face-to-face in a ‘real-life’ consultation right now, I would go through this exercise with you. Since we are not, I need to trust that you are following through this with me.

So, go ahead and find your number right now.

Have you found your BMI?

Now, I’m sure you want to know what this number means.

First, I must say that although BMI does not measure body fat, it has been shown repeatedly to correlate very well with the degree of obesity. It serves as an excellent guideline.

I’ll repeat that: it serves as a guideline. Since body fat and muscle have different densities, it is conceivable that a very muscular person could calculate his BMI and according to the chart he would be obese! Obviously, a doctor’s consideration is always necessary to make clear conclusions using the BMI chart. But, having said that, it is a great place to start.

The most recent obesity categories from the National Institutes of Health were created in 1998. Here is what they have concluded:

If your BMI is less than 19, you are underweight.
If your BMI is 19-24.9, you are of ideal weight.
If your BMI is 25-29.9, you are overweight.
If your BMI is 30-34.9, you are obese.
If your BMI is 35-39.9, you are severely obese.
If your BMI is 40 or greater, you are morbidly obese.

Now that you see the classification system, which category do you fall into?

Are you satisfied with that?

If your answer is “No!”, then please read on…

Before we go much further, I’d like to address a very important issue. The issue is ‘What Really Causes Obesity?’. Let’s tackle that question tomorrow …

Share and Enjoy:
  • Print
  • Digg
  • Sphinn
  • del.icio.us
  • Facebook
  • Mixx
  • Google Bookmarks
  • Blogplay

{ 2 comments… read them below or add one }

eastlandgrl October 18, 2010 at 5:51 am

interesting, thanks

badmash October 23, 2010 at 7:02 am

I just signed up to your blogs rss feed. Will you post more on this subject?

Leave a Comment

Previous post:

Next post: