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People all over the world are obsessed with weight and with good reason. Obesity is on the rise and individuals are stepping on scales to find out just how much they weigh. Lifestyle is becoming more sedentary as “couch potatoes” are on the increase and our children are less active because they are sitting in front of the computer all day. Watching a number bounce on the scale does not tell the whole story about health and the proper ratio between weight and height. This is where Body Mass Index comes into play.

Body mass index is the calculation scientists developed to determine if an individual weighs a healthy amount in comparison to the height of the body. The exact body mass index formula is: weight in kilograms divided by height in meters, squared, or BMI = kg/m2. For example, a person who weighs 140 pounds and is 5 feet 8 inches tall has a BMI of 21.33. There are many calculators located online to easily determine your BMI. Is the body mass index beneficial and what exactly does it tell you? Doctors can identify potential weight problems by knowing the BMI of a patient, however, if it is obvious that a patient is very overweight or extremely underweight; the body mass index doesn’t hold much value. If a patient has a BMI less 18, they are generally considered to be malnourished, or they may have an eating disorder. This would probably be noticeable without the BMI number. If an individual has a BMI of over 30, they are generally thought to be in the obesity range. A person should strive for a body mass index number of 18 – 25. This is the normal range. Keep in mind that two people can hold the same body mass index number, but have different percentages of fat on the body.

Knowing your BMI doesn’t hold all the answers and has limitations. This number does not take into account race, sex, ethnicity or age. A bodybuilder has extreme muscle mass and could have a high BMI but not be overweight. Someone with a very low BMI such as an elderly patient could low to normal BMI, but not be healthy. The BMI is just one factor a doctor would consider when assessing risks for diseases. Lifestyle choices would also need to be considered; such as smoking, drinking, drug use, cholesterol levels, blood sugar levels, family history, diet and exercise.

What else can affect BMI? A study was published on February 15, 2005 in the American Journal of Epidemiology stating that the glycemic index (GI) of dietary carbohydrates is related to body mass index (BMI). The researchers found that BMI was higher in people who ate more foods with high GI carbohydrates, but that the total amount of carbohydrate eaten is not related to BMI. The GI of foods is a measure of how quickly the food causes blood sugar to rise, so high GI foods make blood sugar rise more quickly. High GI foods include refined carbohydrates, such as white bread and pasta and processed foods that contain a lot of sugar. A study was also done at Washington University School of Medicine where genetic predispositions were looked at for parents and naturally born children as well as adopted children. It was found that genetics seemed to have more of an influence on the body mass index of children vs. an environmental influence where no genetics were held in common. Studies have also been done in Japan to see if body mass index could be influenced by the jobs that people held. Factory workers were tested to see if their job stress, shift work, sedentary work, lack of exercise, smoking, drinking and marital status could influence the body mass index and health in general.

Body Mass Index – It’s the same for Kids, Yet Different

Calculating the body mass index works the same way for children. Children as young as two can be assessed in this way. There are differences in that children tend to start out with high amounts of body fat and lose this as they get older. Boys and girls also have different body mass from each other. Because of these differences; the BMI for age was developed. This gives a bigger picture of height, weight and age to determine the amount of body fat. This number can also help doctors predict if a child will become obese as they get older. Teenage girls also generally have a higher percentage of body fat than teenage boys. It is important to keep track of the BMI for children as they age so risks can be assessed if leaning towards obesity as an adult.

Bottom line, calculating the BMI of a patient works as just a tool for the doctor to see if an individual is leaning towards obesity. For many of us, all we need do is take a look in the mirror to see if we are leaning towards obesity. There are many other things that need to be considered for maintaining a healthy body and keeping it free from disease.