Is BMI Best? 8 Steps to Your Healthiest Weight (Op-Ed)

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Katherine Tallmadge, M.A., R.D., is a registered dietitian, author of "Diet Simple: 195 Mental Tricks, Substitutions, Habits & Inspirations" (LifeLine Press, 2011) and a frequent national commentator on nutrition topics. Tallmadge contributed this article to LiveScience's Expert Voices: Op-Ed & Insights.

My clients regularly ask me: Could the height/weight charts in doctors' offices be correct? Really? My answer: It depends . . .

Don't use height/weight charts alone to determine your ideal body weight. Researchers designed the latest body mass index (BMI) charts for use in combination with additional personal information. A group of scientists from the National Institutes of Health (NIH) who specialize in how weight affects health crafted the guidelines after reviewing hundreds of studies conducted over the past several decades — only then did the experts make their recommendations to health professionals.

The guidelines help physicians, and registered dietitians like me, evaluate and make recommendations for clients. But you can also use the BMI charts, along with your doctor's advice, to help you decide what your appropriate weight should be.

Eight steps to reaching your healthy weight

1. Determine your BMI, or the relationship between weight and height that researchers have associated with body fat and health risk. Calculate BMI by dividing your weight (in kilograms) by your height squared (in meters) (kg/m2). NIH has a calculator, so you don't have to do the calculation yourself!

2. If your BMI indicates you are overweight, it is ideal for you to lose weight . That said, weight-loss treatment is particularly important — and recommended — when you have two or more health risk-factors. These include being a smoker, being inactive (I would define "inactivity" as fewer than 10,000 pedometer steps daily, averaged over a week), or having any of the following: high blood pressure, low HDL (good) cholesterol, high LDL (bad) cholesterol, high triglyceride (blood fat) levels, impaired fasting-glucose, a family history of premature heart disease, or a high waist-circumference (measured at the belly button). Here, "high" means greater than 35 inches for women or 40 inches for men. This is important because the presence of abdominal fat is correlated with disease risk. Health professionals used to think body fat was inert, but it isn't — it's toxic! Fat tissue produces hormones and pro-inflammatory chemicals that regulate metabolism, the immune system, inflammation, the progression of artery hardening, and the development of cancers. So, when you have less body fat, you get many biological benefits.

3. If you fit into the obese category, health professionals recommend you undergo weight-loss treatment.

4. Your initial weight-loss goal should be to reduce body weight by about 10 percent from your starting weight. This should take about six months, depending on how much weight you have to lose. You can safely lose one-half to three pounds per week. Assuming your calorie intake is appropriate, the more cardiovascular exercise you do, the faster you can lose weight.

5. If you need to lose more weight, make another attempt at weight reduction.

6. After you reach your desired weight-loss goal, start a weight-maintenance program consisting of dietary therapy , physical activity and behavior therapy. You should continue this program indefinitely.

7. You will need to follow lifestyle therapy for at least six months, according to the NIH guidelines, before your doctor prescribes drug therapy or surgery. However, the safety of drug therapy has not been established, and 50 percent of surgery patients regain lost weight.

8. For the very obese — with a BMI over 40, or a BMI over 35 with significant adverse health conditions — obesity surgery may be an appropriate option.

Note: Highly muscular people, usually professional athletes or body builders, may register as overweight using the BMI scale, but this may be because of high muscle mass instead of fat. More muscle is not generally thought of as unhealthy, so weight loss would not be necessary in these cases.

Tallmadge's most recent Op-Ed was "Stealth Assault on Health: Beverages Pack Calorie Punch,"and her additional contributions are available on her profile page. Her latest book is Diet Simple Farm to Table Recipes: 50 New Reasons to Cook In Season. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This article was originally published on LiveScience.com.

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