What Is an Ideal Body Weight?
Ideal weight is different for everyone. Doctors use weight as one benchmark for health. A “healthy weight range” is based on various factors unique to you, offering doctors a framework that helps them assess your overall health.
Historically, doctors have defined “ideal weight” as the weight at which you’re at the lowest risk of dying. Researchers first got these numbers from life insurance companies at the turn of the 20th century. These scales have continued to evolve over the years.
While your weight is an important health indicator, it’s not the whole story, and achieving a number on a scale doesn’t equal “ideal health.” Your goal should be to maintain a balanced lifestyle that focuses on many different aspects of your wellness.
Factors Influencing Your Ideal Body Weight
Doctors set your healthy weight range based on multiple factors. Your range is unique to your:
Age. As you get older, your metabolism slows down, and hormones shift. These changes affect your weight.
Sex. In general, men and people assigned male at birth (AMAB) have heavier bones and more muscle than women and people assigned female at birth (AFAB) overall. Men and people AMAB of a certain age typically weigh more than women and people AFAB the same age.
Height. When there’s more of your body, you weigh more. The taller you are, the higher your healthy weight range will be.
Medical conditions. Certain health issues or medications can cause weight gain such as corticosteroids, antidepressants, beta-blockers, antipsychotics, and insulin. You gain weight during pregnancy. Chronic stress or poor sleep can also lead to weight gain. Other issues or medications make you lose weight, such as cancer, gastrointestinal conditions, and anxiety.
Body composition. Your body composition measures how much of your body is fat vs. how much is nonfat. If you have a high muscle content and low body fat, you may weigh more than someone else of the same sex, age, and height but still be within an “ideal” range, as muscle weighs more than fat.
Genetics. Your genes direct how full you feel as you eat, your appetite levels, and how your body uses energy and burns calories, all of which can affect your ability to gain or lose weight.
There are different ways to calculate ideal weight. For example, some methods create a range, while others result in one number. Some calculations take into account your sex, while others use ratios of certain body measurements to your weight.
Body Mass Index (BMI)
One tool doctors have long used for measuring ideal body weight is body mass index (BMI). It’s a measure of your body weight in kilograms divided by the square of your height in meters. You can calculate your BMI with a simple online BMI calculator.
The BMI ranges are as follows:
- Obesity = 30.0 or above
- Overweight = 25.0 to 29.9
- Healthy weight = 18.5 to 24.9
- Underweight = under 18.5
BMI can give you an idea of where you stand, but it doesn’t measure body fat. It’s not meant to give a diagnosis or confirm if you have a weight problem.
BMI has faults. For example, it can’t tell the difference between fat and muscle, so it can be off when someone is very muscular or has lost muscle mass. Muscular people might have a high BMI without being obese. And BMI can underestimate fat in older people and others who have lost muscle. It also doesn’t determine where excess body fat is distributed.
The BMI calculation was created in the 19th century by a mathematician, not a doctor. Later in the 21st century, a physiologist adopted it for statistical research, not medical use. The research he did with BMI also included primarily non-Hispanic men and didn’t account for other races or ethnicities.
Because of this, BMI isn’t a good tool for everyone. For example, studies show that Asian adults may be at higher risk of heart disease and type 2 diabetes at a lower BMI than White adults.
Your BMI alone should never be a measure of your health. If you think you have obesity or have questions about healthy weight, talk to your doctor.
Waist Circumference
There’s another way to get an idea of how an unhealthy weight might affect your health — just measure your waist.
The waist is key because tummy fat can be more serious and is linked to metabolic and cardiovascular risks. This puts you at greater risk of things such as type 2 diabetes, high blood pressure, and heart disease.
Your waist doesn’t show for sure that you’re overweight. Both BMI and waist measurements are screening tools. But in general, here are the guidelines for men/people AMAB and women/people AFAB:
- Men and people AMAB: Waist should be no more than 40 inches.
- Non pregnant women and people AFAB: Waist should be no more than 35 inches.
Here’s how to measure your waist:
- Stand up and wrap a measuring tape around your waist (just above the hip bones).
- The tape should be snug but not pressed into your skin.
- Breathe out before you measure.
Waist-to-Hip Ratio (WHR)
You get your WHR by taking the circumference of your waist and dividing it by the circumference of the widest part of your hips.
Your WHR tells your doctor where you fall in the range of excellent to at risk.