6 Reasons Ideal Weight Charts Don’t Fit Everyone

“Ideal weight” sounds like a precise medical term. It isn’t, and its actual origin story explains why the number doesn’t fit everyone equally well.

1. The concept came from a life insurance company, not medical research

The idea dates to 1959, when the Metropolitan Life Insurance Company published tables linking weight to mortality risk among its policyholders, originally to help price insurance policies. They were even called “ideal weight tables” at first.

2. The insurer itself later renamed them

Metropolitan Life later changed the name to “desirable weight tables” specifically because “ideal” was considered misleading. The scientific community has continued to question both the original methodology and the terminology ever since.

3. They didn’t account for health conditions or lifestyle

The original mortality data didn’t control for smoking, pre-existing conditions, or family health history, factors that clearly affect mortality independent of weight, which weakens the direct weight-to-health link the tables implied.

4. Formulas like Devine were built for a completely different purpose

Devine, Robinson, Miller, and Hamwi weren’t built as fitness targets at all. They were developed decades later to estimate lean body mass for medication dosing, particularly for drugs with a narrow safety margin, and only later got adopted as general wellness reference points.

5. They assume weight scales with height alone

These formulas treat weight as a simple linear function of height, but real body weight also depends on frame width, trunk length, and muscle mass, none of which the base formula captures without a separate frame-size adjustment.

6. They were built from limited, non-diverse populations

Much of the underlying data came from predominantly white, middle-class American cohorts of the era, which may not generalize well to the full range of body types and ethnic backgrounds using these formulas today.

What this means for using the number

These formulas remain genuinely useful for their original clinical purpose, estimating lean mass for medication dosing, and as one general reference point among several. Our ideal weight calculator shows all four formulas plus a frame-size adjustment specifically so you see a range, not a single misleadingly precise number. See our full breakdown of how each formula works for the underlying math.