The Body Mass Index (BMI) is a tool to help evaluate overall health relative to height vs. body weight. It is a formula as follows:
Height (in inches)/(weight in lb squared) x 703
The BMI is NOT a direct measurement of body composition or body fat.
The BMI is how we categorize people’s health risk based on their body weight as they (the medical research) have been able to correlate some diseases with the BMI. According to the ‘experts’ the higher the BMI the higher the risk. The BMI categories are based on the relationship between weight, disease, & death.
The BMI recommended by the medical community as a tool to help determine health risk. It is true that excess body fat decreases health but the BMI does NOT correlate with body fat.
Dr Robert Huizinga, the Medical Director for NBC’s hit show ‘The Biggest Loser”, calls the BMI the Bogus Medical Index and for good reason!
I had the opportunity to work with Dr Huizinga for several days and it was quite enlightening! During his presentations he presented 3 patients and showed pictures.
- A young girl with a BMI of 18
- A ‘Beverly Hills Housewife’ with a BMI of 22
- A patient with a very large abdominal ‘pannus’ which is a large over-hang of the abdominal skin and fat
He would then ask which patient was the healthiest and which one was the ‘fattest’. Interestingly, they all had the same percent body fat at around 33%! The first patient with a BMI of 18 had what is called Sarcopenia (very low muscle mass) and was extremely unhealthy! Clearly, the BMI is not an accurate tool for this patient.
Next, he presented a male patient who was 25 yrs old, 6’1″, and weighed 270 lbs. He then mentioned that his BMI was 35 which qualified this patient for gastric bypass surgery. This patient was… Bo Jackson! Dr H described him as the fittest man he had ever had the opportunity to work with.
Any system that can confuse an extremely fit man for an obese man who needs gastric bypass is obviously flawed!
The BMI can help put patients into categories somewhat and it is certainly cheaper than performing a DEXA body composition scan on all of our patients. However, we do recommend DEXA scans for our Revolution Health & Wellness Clinic patients.
The categories are as follows:
- Underweight: <18.5
- Normal weight: 18.5-24.9
- Overweight: 25-29.9
- Obese: 30-39.9
- Morbidly Obese: >40
As stated above, the higher your BMI the higher association for many medical problems such as:
- Type 2 Diabetes
- Coronary Artery Disease
- Gall bladder disease
- Sleep Apnea
- Cancer (some, such as breast, colon, and endometrial)
The bottom line is that unless your body fat percentage is less than 15% (slightly higher for women) AND your BMI puts you in the overweight or obese category YOU NEED TO LOSE WEIGHT!
Here are some additional resources regarding weight & BMI
- CDC BMI page
- My weight loss page
- National Heart, Lung, and Blood Institute’s BMI page
- BMI Calculator
- The Biggest Loser