Body Mass Index (BMI)
The most common method of scaling obesity is the concept of a Body Mass Index (BMI) that takes into consideration gender, height and weight. This chart can be found on the U.S. Department of Health and Human Services, National Institutes of Health website on adults and obesity, ‘Understanding Body Mass‘ here. (Dept. of Health and Human Services)
What this index or chart represents is an average suggested “ideal” or normal body index factor broken down by gender, with a range that moves from an average score of 19-24 for “normal” to a score of 25-28 classified as “overweight”, to a score of 30-39 as “obese” and specifying a range of 40-43 as “extremely obese”.
The chart is broken down by height and serves a general purpose of identifying how overweight someone really may be but it’s limitations includes it’s starting height at 4’10” and ending at 6.2″.
This means people who are height challenged, like dwarfs or those who are over 6’2″ are excluded. For an “average” man who is 5’10” tall,the maximum weight on the chart for an extremely obese man is 292 pounds, and a 6’2″ maximum for a man is 326 lbs.
We all have heard stories of people who are 400lbs plus. This scale doesn’t include a “life threatening” category but maybe it should. This scale also doesn’t take into consideration the age of a person, and it has recently been suggested that seniors should have their own scale due to bone density changes that occur naturally as people age.
How to measure body fat
On the BMI body mass is calculated by dividing a person’s weight in pounds by height in inches squared and multiplied by 703.” (Department of Health and Human Services). As their website suggests, the BMI has other limitations. Namely the breakdown of body mass into sub categories of fat, muscle and bone density are not taken into consideration. Nor is the lifestyle or age of person used in determining body fat vs. body mass.
The site suggests that a health care professional can use this index as a red flag warning system to help them gauge and look for possible health issues if someone falls outside of the suggested normal range but to take into consideration other inputs.
A visual physical assessment for fat deposits around the waist, in the thighs, buttocks, in the face, around the neck and chest, as well as hands and feet, will provide the health care provider with a more in-depth understanding of potential obese areas. Additionally, a psychological profile can be made by asking questions about lifestyle choices regarding food, exercise, sleep, and general health. The answers can provide clues to possible risky behavior that lends itself to obesity.
Why is measuring body fat important?
Carrying extra weight can be a burden on the heart, the pulmonary system, and excessive fat specifically in the waist area can lead to other proven health risks such as gout, fertility problems for women, and Osteoarthritis; a disease in which joints deteriorate. (Understanding Body Mass)
How to measure body fat
Northwest Health University’s ‘Keep Lean’, says that body fat, rather than mass, can be measured in three ways.
Using calipers to measure “fat rolls” or fat density is one method, but there is variance due to human interpretation. Experience will play a large role, and there will be variations in interpretations from one person’s measurement to another.
Bioelectrical Impedance (BEI) is another method of measuring body fat, as the percentage of fat to body mass is what is most important. Northwest goes on to say that the third way, the crème de le crème or gold standard of fat measurement is underwater measurements. The problem for most people is that they don’t have access to the right equipment to perform this test.
While the BMI index has been the standard for many years for the health care profession, new studies have proved that additional inches on the waist cause specific, measurable health risks.
Taking a simple look in the mirror is enough for most people to know whether or not they are overweight, obese, extremely obese, and/or if the body fat is disproportionate in the waist area.
The key to managing body fat is to balance the intake of calories with the outgo of energy. As people age, their bones become less dense, they typically become less active, and their metabolism slows. If they don’t adjust their intake of calories and fat with their outgo of energy, they will end up carrying more weight than their body can handle.
Reducing body fat
Fortunately, reducing body fat at any rate is desirable and even small adjustments such as adding a daily 20 minute walk and reducing salt, sugar and fat intake modestly can significantly improve overall health and improve energy levels. “Research shows that a 5- to 7-percent weight loss brought about by moderate diet and exercise can delay or possibly prevent type 2 diabetes in people at high risk for the disease.” (National Institute of Diabetes and Kideny Diseases)
Finally, the March 2004 edition of the American Journal of Clinical Nutrition says additional inches, can cause specific and measurable differences in a person’s health. For example, they found that for “every 1 inch increase in the waist circumference in men the risk for high blood pressure increased by 10%.” To see more about this study and potential health problems with a bulging tummy, see here.
The National Institute of Diabetes states, “Women with a waist measurement of more than 35 inches and men with a waist measurement of more than 40 inches may have more health risks than people with lower waist measurements because of their body fat distribution.” (National Institute of Diabetes, and Kidney Diseases)
U.S. Department of Health and Human Services, Adults and Obesity, Understanding Body Mass
Janssen Ian, et al, Waist circumference and health risk, Amer J Clin Nutr 79:379-84, Mar 2004; ShanKuan Zhu, et al, Waist circumference and obesity-associated risk , Amer J of Clin Nu, 76:743-9
Northwest Health University’s ‘Keep Lean’