You step on the scale and are pleased to see you’re “ideal body weight” based on the medical charts. The formula doctors use to calculate ideal body weight for women is: 100 pounds for the first 5 feet of height and 5 pounds for each additional inch over 5 feet. For example, a 5’6″ woman would be ideal body weight at 130 pounds. For men, the formula is 106 pounds for the first 5 feet of height and 6 pounds for each additional inch of height over 5 feet.
Even though this is a simple formula that’s handy for calculating ideal body weight, it says little about a person’s overall health or their risk factors for heart disease, type 2 diabetes and other health problems. It doesn’t even give an indication of what type of shape you’re in. The weight a traditional scale spits back to you measures the weight of your organs, bones, fat tissue and muscle tissue. It reveals nothing about body composition – how much of your body weight is muscle tissue and how much is fat. For that, you would need a scale that measures body fat percentage.
Limitations of the Scale and Ideal Body Weight
If you’re 5’4″ and weigh 120 pounds, you may get a false sense of security when you step on the scale. After all, you’re at your ideal body weight – but what if your weight is 120 pounds and your body fat percentage is 35%? That certainly wouldn’t be a reason to celebrate. There are a significant number of people, particularly inactive people over the age of 40, who are skinny-fat. In medical lingo, this is called sarcopenia. It essentially means your weight is normal, but you’re carrying around too much body fat. As a result, you’re at greater risk for health problems.
How healthy you are has more to do with the amount of body fat you’re carrying than how much you weigh when you step on the scale. That’s why some athletes weigh more than their ideal body weight, but much of that weight is lean body mass or muscle. The number the scale spits back at you has to be taken in context.
Other Ways to Assess Body Composition and Health
So how do you know if you’re a “healthy” body weight or an unhealthy one? You can invest in a scale that measures body fat percentage, although not all of them are accurate, and your measured body fat percentage can vary depending on factors like how hydrated you are. You can also use calipers to measure body fat with some degree of accuracy. The other way to find out more about your body composition and health risk factors is to get out the tape measure.
The circumference of your waistline reveals more about general body composition and risk for health problems than the scale does. When you have a large waistline, you have too much visceral fat, the kind of abdominal fat that lies deep within the pelvic cavity. This is the type of fat that increases the risk for health problems like heart disease and type 2-diabetes. The “danger zone” is when a woman’s waistline grows to 35 inches or larger or a man’s is over 40 inches. That’s when the risk for health problems starts to climb, and the tape measure is a quick and easy way to see if your body composition puts you at greater risk.
The Bottom Line?
Don’t use the scale as an indicator of how healthy you are from a body composition standpoint. It gives you limited information. Use calipers or a body fat scale to measure your body fat percentage and a tape measure to measure the circumference of your waistline. It’ll give you a better idea of where you stand in terms of body composition and health.