What’s Normal Weight For A Woman And Why Is BMI Unreliable?
Please note: This BMI information only applies to adults.
What is a normal weight? I’m a five-foot-seven-inch-tall woman. At least I am if you round up to the nearest inch! And I’m “normal weight” for my height. Don’t confuse normal weight with average weight. On average, American women aged 20 and older weigh 170.6 pounds, have a waist circumference of 38.6 inches, and are 5 feet 4 inches tall.
All sounds a little judgmental? Normal weight is simply a term used by medical professionals to indicate a healthy body weight range and refers to body mass index (BMI). It’s not an average weight, but an easy way to find your ideal weight range.
Find Your Body Mass Index (BMI)
To find your Body Mass Index (BMI):
- divide weight in kilograms by height in meters.
- divide the answer again by height in meters.
Or use this BMI chart.
Normal just means I’m probably not underweight, overweight, or obese. BMI has many limitations and can be highly inaccurate, but it’s a quick, easy way to estimate your ideal weight. You just need to be careful if you’re using it as a guide for weight loss.
What Is Normal Weight?
Normal weight, for a five-foot-seven-inch-tall woman, is in the range of 118 to 159 pounds.
Now that’s a huge range. It reflects different builds, and you’ll find some older BMI charts that refer to small frames, medium frames, and large frames.
Why Is It Important To Have Normal Body Weight?
The BMI score is a rough-and-ready indicator, but maintaining a normal weight can be important. It’s not about looks or being “bikini ready”. Statistically, your weight reflects your health.
If you’re overweight or obese, you could be playing Russian Roulette with your overall health. Medical conditions such as diabetes, heart disease, types of cancer, and strokes are all possible consequences of the health risk of being overweight.
That said, weight isn’t everything, and I’m all in favour of the body positive movement. Your life shouldn’t be dictated by the numbers on a scale. Yet carrying around a lot of excess weight isn’t just a health risk. It’s hard work. Whenever I’ve piled on some extra pounds, walking upstairs at my usual pace leaves me out of breath.
Is BMI Accurate?
BMI was a formula dreamt up in the 19th century by a Belgian named Lambert Adolphe Jacques Quetelet. He was a mathematician who developed the BMI formula to measure obesity in the general population. It was never intended for individuals. While a person who is overweight or obese will have a high BMI, the reverse isn’t true. You can have a high BMI but not be overweight or obese.
These are some of the factors affecting your BMI result:
1. Body Frame
Your body frame or build is reflected in your weight. That’s why the BMI range of a particular height is so large. I’m sure you’ve heard the claim that someone’s just big-built rather than overweight. Sometimes it’s true. Yet assessing someone’s frame adds yet another layer of inaccuracy. It’s based on your wrist circumference:
For a woman over 5′ 5″
- Less than 6.2 inches indicates a small frame,
- 6.2 to 6.5 inches indicates a medium frame,
- Over 6.5 inches indicates a large frame.
Based on this measurement, I have a small frame. Maybe I have, but I also have a really broad back. It seems odd to me that body frame can be based purely on your wrist size. The BMI calculation is vague enough without trying to account for frame size.
2. Sex – Man vs Woman
The BMI calculation doesn’t account for differences in biological sex. Men and women have different body shapes and body fat percentages, and men, because of testosterone levels, tend to be more muscular. All of these have significant implications for your weight. Failing to differentiate by gender limits the effectiveness of BMI.
3. Muscle Weight
The BMI weight chart doesn’t account for athletes who carry extra muscle mass. It’s quite normal to find muscular athletes with very low body fat but with a high BMI, mistakenly indicating they are overweight or even obese. You can be obese based on your BMI calculation and yet be anorexic with dangerously low body fat levels.
There’s currently insufficient information about the relationship between health and muscle weight. If you do have big muscles, make sure you also have good cardio.
Don’t Get Hung Up On Your Normal Weight
Let’s get a bit of perspective here. A lineup of 5-foot-7-inch-tall healthy women will give you all different shapes and sizes. There is no such thing as normal. Normal weight is really just an average indicator across a population.
Of course, it would be wrong to deny weight gain has an impact on the health of a nation. Since the 1960’s the average American woman has gained less than an inch in height but 30 pounds in weight. In the same timeframe, diabetes in the United States has increased rapidly. Almost 30% of the US population over 65 now has diabetes. It’s not surprising that some of this increase is attributed to weight gain.
For a lot of women, constantly focusing on weight, calorie intake, and dieting leads to a life of misery. It’s better to foster a healthy relationship with food, eat better rather than less, and move more. Being fit will help you feel better about your body. It’s a better route to being healthy.
