01/03/2013 12:59 pm ET Updated Mar 05, 2013

Want to Lose Weight? Measure Your Height!

Have you stepped on a scale lately? I bet you have -- most of us check our weight around New Year's. And after viewing the number, you probably resolve to lose a few pounds over the next few months. If you haven't checked your weight, you should. But you also need to measure your height. You read that right --- how tall you are also helps determine how much you should weigh.

Nowadays, simply knowing how much you weigh isn't enough information to be as healthy as you can be. You need to know your height, since the relationship of weight to height is critically important in determining your overall health.

This weight-height measurement is known as body mass index (BMI). It's important that you know your BMI because that lets you know if you are normal weight, overweight, or obese. You cannot look at yourself in the mirror and pinch your belly, and then decide how much weight you need to lose. We all do that at some point, but it doesn't work. Today, we need a little more information to determine a healthy weight.

All you need is a tape measure and a willing partner to help measure how tall you are. And you only need to measure height once. But you have to actually measure it. I can't tell you how many people -- especially men -- always seem to say they are taller than they actually are. It is true that we start to shrink as we get older, so perhaps you're thinking of your height in college -- and chances are you are shorter today. But shrinking occurs over decades -- so if you check your height today, you'll be good for a few years.

You don't need to break out the pencil and pad for high-level math. Simply use this online calculator.

Once you know your BMI, you can then determine how much weight you need to lose. This table
provides the information you need so you can see how much you should weigh. Most people really don't know how much they should weigh. For example, if you're 5'5" and you weigh 156 pounds, your BMI is 26, which puts you in the category of overweight. Following the chart, you should weigh between 114-144 pounds. If you're 4'11" and weigh 148 pounds, you have a BMI of 30, which is considered obese. You need to weigh between 94-119 pounds, according to the chart.

BMI has come under some controversy over the past few years. BMI does not take into account how muscular a person can be. And therefore definitions of overweight and obesity as determined by BMI do not apply to a very fit athlete or muscular person. That's partly because muscle weighs more than fat, so a muscular person's excess weight is not necessarily harmful. But let's be realistic -- 99 percent of us are not in that category. There's always someone who says to me, "Dr. Whyte, I'm not overweight; I'm muscular." Honestly, never has that been the case; they've never been so muscular that it skews the definitions for them. And usually people that are overly muscular and fitness fanatics are pretty healthy to begin with! That's not most of us.

We know from numerous studies that the higher your BMI, the greater your risk of diabetes, heart disease and high blood pressure.

We've also recently learned that BMI may predict your risk of a heart attack even more accurately than cholesterol tests.

So how tall are you? How much do you weigh? What's your BMI? How much should you weigh? Answer these four questions and you'll be well on your way to a healthier you in 2013!

For more by John Whyte, M.D., MPH, click here.

For more on weight loss, click here.