Beyond the Numbers: Why the BMI Scale Is Failing Women

May 6

The Body Mass Index (BMI) has been used for decades as a health assessment tool—but it's deeply flawed. Created in the 1830s by a Belgian mathematician, BMI was never intended to evaluate individual health. Yet today, it continues to influence medical care, insurance, and even self-worth.

This blog explores the history of BMI, how it became medicalized, and why its limitations are especially harmful to women.

🧮 The Origins of BMI

In the early 19th century, Belgian mathematician and statistician Adolphe Quetelet developed the “Quetelet Index”—a mathematical formula dividing weight by height squared. It was never designed to diagnose health or body fat. Quetelet’s work was purely statistical and focused on identifying the average physical traits of European men for population studies—not clinical care.

🧪 How BMI Was Adopted into Medicine

Fast-forward to 1972: Physiologist Ancel Keys published a paper in the Journal of Chronic Diseases endorsing BMI as a practical, if imperfect, way to assess obesity across populations. Keys stated that BMI was “at least as good as any other relative weight index” for population studies, opening the door for broader adoption.

By the 1980s and 1990s, organizations like the World Health Organization (WHO) and the National Institutes of Health (NIH) adopted BMI as a global standard for categorizing weight. It became the foundation for diagnosing underweight, “normal weight,” overweight, and obesity.

What began as a statistical convenience became a clinical mainstay.

⚠️ The AMA Speaks Out

In 2023, the American Medical Association (AMA) formally acknowledged the serious limitations of BMI as a medical tool. They noted BMI’s racist and exclusionary roots and declared it should not be used as the sole measure of individual health.

“The AMA recognizes issues with using BMI as a measurement because it does not account for differences across race/ethnic groups, sexes, genders, and age-span.”
— American Medical Association, 2023

Instead, the AMA urged clinicians to consider other indicators—such as waist circumference, body composition, genetic factors, and metabolic health.

💔 Why BMI Is Failing Women

The one-size-fits-all approach to BMI is particularly harmful for women. It ignores body composition, hormonal fluctuations, life stages, and differences in muscle mass. For example:

A woman who strength-trains may have a high BMI but low body fat.
A postpartum mom may carry more weight but be metabolically healthy.
A woman in perimenopause may gain weight due to hormonal shifts—not poor health.

BMI can lead to false assumptions and harmful labels like “overweight” or “obese,” which don’t reflect what’s really going on in a woman’s body.

🧬 The Emotional & Medical Fallout

Using BMI as a health standard contributes to:

Shame & Body Image Issues: Women are often told to shrink themselves to meet a number—regardless of health.
Delayed Care: Those in “normal” BMI ranges can be overlooked for serious issues, while others are dismissed as “just needing to lose weight.”
Eating Disorders: According to the National Eating Disorders Association, weight stigma and pressure to conform to BMI categories are risk factors for eating disorders.

✅ What to Use Instead

Instead of relying on BMI, a holistic health assessment should include:

Body composition (e.g., InBody, DEXA)
Hormone labs (insulin, estrogen, thyroid)
Blood sugar markers (fasting glucose, A1C)
Energy levels, mood, menstrual health
Strength, stamina, digestion

🌟 Final Thoughts

Your worth—and your health—are not defined by a number on a chart. It’s time we move past BMI and look at the full picture.

Women deserve care that recognizes muscle, metabolism, hormones, and life context. Let’s shift the narrative from "how much you weigh" to "how well you function and feel."