Being either underweight or overweight can be detrimental to your health, so it's important to know where you fall on the scale. This can actually be harder to determine than you may think. Some of the methods for determining whether you are underweight or overweight can work for the average person, but they don't take body composition into account. The best way to know where you stand is to have a doctor examine you.
Doctors typically use weight charts to plot the weight of children over a period of time, but there are also charts that can tell the normal weight range of adults. Weight charts give you a low number and a high number. Your goal should be to fall somewhere in the middle. If you are below the number, you are underweight, and if you are above the number, you are overweight. For example, a 5-foot-4-inch woman should weigh between 114 and 134 pounds, and a 5-foot-8-inch man should weigh between 140 and 172 pounds. Weight charts can be good for giving you a general idea of where you should be, but they don't consider muscle weight. Someone that is athletic will weigh more on the scale but not be overweight. This is because muscle is heavier than fat.
Body Mass Index (BMI)
The Body Mass Index, or BMI, is a simplified form of the height-weight chart. To find your BMI, you would divide your weight in pounds by your height in inches, then multiply the result by 702. If the resulting number is below 18.5, your doctor would consider you underweight. If it's between 25 and 30, you are overweight, and if it's over 30, you are obese. While doctors often use BMI as the primary method for determining whether a patient is underweight or overweight, it, too, can be inaccurate if the person is very muscular.
Body Fat Percentage
Your body fat percentage is the percentage of your weight that consists of fat. It is a more accurate representation of whether you are underweight or overweight because it takes your body composition into account. Online calculators can give you an estimate of your body fat percentage, but it's more accurate to have your doctor perform tests to determine it. Your doctor may perform a skin caliper test, which pinches the fat to determine how much fat you have, or a water displacement test, which measures fat by how much water you displace when you immerse yourself in a tank. You can also purchase a home scale that measures body fat percentage. The home scale uses bioelectricity to determine your body fat and can vary greatly depending on how much water you drink, but it can still give you a good idea of where you stand if you measure at the same time every day. For women, the normal body fat percentage is from 14 to 31 percent, with only serious athletes in the 14 to 20 percent range. The normal range for men is 6 to 26 percent, with only athletes in the 6 to 13 percent range. Anything below these percentages is underweight and anything above these percentages is overweight.