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BMI – Separating Facts From Fiction

From time to time I read comments or articles that are critical of judging a person’s weight by using the Body Mass Index (BMI). I have heard that there is a recent film that calls its usefulness into question. Being a physician, I thought I should clarify some of the more common misconceptions surrounding it. In my next few posts I’ll discuss some of the more common myths about the BMI and point out some facts to help you understand how it should be used and why it’s important:

Myth 1 – BMI Doesn’t Really Measure Obesity

This one is partially true. The BMI uses a person’s weight & their height to calculate a measure that best approximates a person’s bulk. Clearly weight alone is not helpful since it varies according to height. Including height tends to make BMI measures more comparable. The one big flaw is that it cannot distinguish the body composition of an individual – how much of their weight is due to fat versus muscle or bone. Consequently, a muscular weight lifter who has a low amount of body fat may have a BMI that suggests he is overweight or obese. All health care professionals are aware of this limitation and would not draw any conclusions about a person’s health based on their BMI alone. But you just have to look around to realize that most of our fellow Americans are not body builders and the odds are that an elevated BMI in an American is due to an excess amount of fat.

Bottom Line: While BMI alone isn’t a perfect measure of a person’s body fat, it gives a good approximation.Health care professionals will consider it and other measurements in assessing the proper weight range for an individual.

In my next post I’ll discuss another myth I’ve heard that the BMI really is not useful.

For Your Health – Dr. Bob

Obesity & Health

There are a number of reasons why people choose to lose weight.  Some of the most powerful motivators are often very personal, such as wanting to look more attractive to one’s spouse and put the zing back in their relationship.  Beyond these, there are definite health benefits to lowering your BMI into the normal range.  So if you are on the fence about whether to lose weight, the following might help you make up your mind.

Being overweight or obese increases the risk of developing many diseases and conditions including high blood pressure, coronary heart disease, stroke, type 2 diabetes, sleep apnea, high cholesterol levels, high triglyceride levels, osteoarthritis and gallbladder disease. It even increases the risk for endometrial cancer, breast cancer and colon cancer.

During pregnancy, obesity increases the risk of death for both the baby and the mother and raises the maternal risk of high blood pressure by a factor of ten. The woman who is obese during pregnancy has an increased risk of gestational diabetes and problems with labor and delivery. The infants of these obese women have a higher birthweight which leads to a higher rate of cesarean section with its higher rate of complications. These infants often have low blood sugar which can lead to brain damage and seizures. In addition, these infants have a higher risk of birth defects.

The attainment of a normal weight can lower these risks. A report from the Surgeon General stated that an overweight individual can reduce their risk of heart disease even by just losing 5-15% of their body weight. So there is definitely hope to improve your health risk.

A Simple Formula

Being overweight or obese is due to an energy imbalance. More calories are eaten or consumed than are used in the activities of the body. To lose weight you must do the opposite:

Formula For Weight Loss: Calories Out (Activity) > Calories In (Food Eaten)

Body weight is the result of heredity, environmental factors and individual behaviors. While you can’t change your heredity, you can alter your environment and your individual behaviors. That is where your power lies. You’ll lose the most the fastest when you eat less and burn more. So, an exercise regimen is an important part of the formula. After being cleared by your doctor, you will need to build up your routine, but it will be worth it!  In addition to helping you lose weight, exercise provides other health benefits including improving your cardiovascular fitness.

For Your Health – Dr. Bob

Barriers to Your Success

Whenever you take steps to change your lifestyle behaviors, whether to stop smoking, eat healthier or begin an exercise plan, it pays to take some time and identify the barriers to your plan.  These are the roadblocks to your success.  They are usually easy to list since they are often related to your list of Cons.

So if we consider the healthy eating plan that must be followed to lose weight, barriers might include:

  • Not knowing what to eat and what to avoid
  • Not knowing what are proper portion sizes
  • Not understanding food labels
  • Having difficulty finding the time to do some research on proper nutrition
  • Being tempted by unhealthy snacks at work
  • Being a frequent snacker
  • Eating out frequently, possibly due to business travel

Barriers to starting an exercise program to help lose weight and for its other benefits often include:

  • Having difficulty finding the time to exercise
  • Not having access to a place to exercise
  • Being embarrassed to exercise in front of others due to self consciousness about being overweight
  • Physical limitations

These are the potential reasons why you may fail in your plan – if you don’t determine how you can overcome them.  So when you make your list of barriers, you need to list next to each barrier what you will do to counteract them.  This way, when you are faced with the barrier, you will know how to respond.  For instance, if you are unsure of what to eat and what to avoid as well as appropriate portion sizes, you need to do some research online or at the library.  To help with portion sizes, you may need to buy a scale and measure all your portions.  When you take the time to identify your barriers you can usually strategize how to eliminate them before you are faced with their challenges.  Including barriers and their solutions in your plan preparation can help assure your success.

Next time I’ll talk about a few more important parts of your healthy lifestyle behavior change plan.

For Your Health – Dr. Bob

 

Pros And Cons

As you identify your motivations for changing your habits of eating and exercise in order to lose weight, listing the pros and cons of making the changes can be helpful. This process helps to validate your decision to make those lifestyle changes.

The actual process is simple. Just draw a vertical line down the middle of a sheet of paper. Then at the top of the left column write Pros and on the right, Cons. Take some time to list reasons for making the change on the left and the reasons not to make the change on the right. Most people easily come up with more reasons to change their behavior than reasons not to make the effort.

For weight loss, most people list the health benefits, improvements in appearance and increases in confidence as the main benefits they will obtain if they lose weight. The health benefits alone include decreasing the risk of heart disease, diabetes and certain kinds of cancer. In addition, weight loss decreases the stress on your knees and hips.

The negative aspects of changing one’s eating and exercise habits is that it isn’t easy and requires work. You need to take the effort to substitute your new healthier behaviors for your old unhealthy ones.

After my heart attack, finding motivation wasn’t very difficult. The pros of minimizing my chances of having a second heart attack or dying far outweighed the work necessary to change my habits. Ideally, you won’t have to have a heart attack before you change your lifestyle for the better.

Save your list of pros and cons. When you get discouraged as you work through your behavior changes, pull it out to remind yourself of the benefits you’ll get if you reach your goal.

For Your Health – Dr. Bob