If you're trying to lose weight and get in shape, then you may be relying on the scale to track your progress. And it's a good place to start; after all, how else are you supposed to determine if your bodyweight is going down than by weighing yourself each week?
Turns out, there are many other ways to track not only weight loss but also overall health: body mass index [1] or BMI, body fat percentage, and waist circumference. Especially as you start to work out and build muscle, the scale isn't always indicative of overall health [2], which is why people are turning to BMI, body fat percentage, and waist circumference to track their progress.
Of these three, the best indicator of overall health is body fat percentage, explained internist Susan L. Besser, MD, MBA, FAAFP, diplomate of the American Board of Obesity Medicine. She said BMI and waist circumference can be less accurate, especially since BMI relies on a chart [4] that is calculated by your weight and your height.
"BMI, which is a person's weight divided by his or her height, may be elevated if that person is very muscular, as muscle weighs more than fat," she told POPSUGAR. "So the BMI will appear high, even though that patient actually is not obese."
Waist circumference is a good measure of central obesity, or belly fat, which puts people at a higher risk of heart disease [5] and diabetes. But Dr. Besser said it's less accurate for people who aren't overweight but just have a larger middle.
Of all these, body fat percentage [6] is the most accurate and best indicator of overall health. It's measured using an air displacement plethysmograph, or BOD POD; a DEXA scan, which stands for dual-energy x-ray absorptiometry; or a bioelectrical impedance analysis.
However, since body fat percentage has to be measured using specific tools only found at specialty institutions, not necessarily at your doctor's office, it may be best for you to rely on your bathroom scale — just don't get too hung up on the numbers, Dr. Besser said.
"A two- to three-pound daily fluctuation is expected," she added. "As you add exercise, your waist circumference and other measures may shrink while your weight doesn't change." As you work out more, your body will lose fat and put on muscle [8]. Since muscle is more dense than fat and takes up less room in the body, your measurements may go down and your clothes may fit better, but the number on the scale may still not budge.
In general, she said BMI and waist circumference can be used to track overall health and weight-loss progress, but if you can, get your body fat percentage measured. If that's not an option, then stick to your bathroom scale — just remember that the numbers on it don't tell the whole story.