What is the healthy BMI range for seniors?

Research suggests the lowest all-cause mortality in adults over 65 is at BMI 25–27, slightly above the standard "healthy" range of 18.5–24.9. This is sometimes called the obesity paradox. A BMI in the low-overweight band for a 75-year-old is often a better place to be than a BMI in the "healthy" band.

Why is BMI less useful in older adults?

Older adults lose muscle mass (sarcopenia) and redistribute fat from subcutaneous stores toward visceral and ectopic stores. BMI can stay stable or even decrease while body composition worsens. Waist-to-height ratio and measures of grip strength and physical function capture the risk BMI misses.

Should older adults try to lose weight?

Unintentional weight loss in older adults is a stronger risk signal than being slightly overweight. Intentional weight loss should usually focus on body composition — preserving muscle through resistance training and adequate protein — rather than the scale number. Any weight-loss plan should be discussed with a clinician.

BMI for Older Adults (65+) — Why the Rules Change

The short version

The mortality-lowest BMI in adults over 65 is around 25–27, not 22. This is the “obesity paradox” — and it's reproducible.
BMI hides sarcopenia (muscle loss with age) and visceral fat redistribution. Someone with a “healthy” BMI can still have poor body composition.
Unintentional weight loss is a bigger red flag than being slightly overweight in this age group.

What the evidence actually shows

A 2014 meta-analysis of 197 studies (Winter et al., American Journal of Clinical Nutrition) found that in adults aged 65+, the BMI range associated with the lowest all-cause mortality was 24–31 — with the nadir around 27. A BMI of 22, often held up as the textbook “optimal” value, was associated with measurably higher mortality than a BMI of 27 in this age group.

This isn't because fat becomes protective with age. It's because:

Muscle mass falls with age. Without active resistance training, adults lose roughly 3–8% of muscle mass per decade after 30, accelerating after 60. A “normal” BMI at 75 often means low muscle and relatively high fat.
Muscle reserve matters during illness. Recovery from infection, injury, or surgery depends heavily on muscle mass and strength. Patients in the low-normal BMI range have less reserve to draw on.
Unintended weight loss signals something is wrong. It's often the first sign of cancer, dementia, depression, or organ failure. Having a little weight to lose is a buffer against exactly this.

What BMI stops capturing after 65

Sarcopenia. Muscle loss without obvious weight loss — the scale and BMI stay flat, but strength, mobility, and metabolic health decline.
Visceral fat redistribution. Fat moves from subcutaneous stores (hips, thighs) toward the abdomen and organs. The same BMI at 75 typically means more cardiometabolically-harmful fat than at 35.
Frailty. A combination of low muscle mass, low strength, and reduced physical function, which predicts falls, hospitalisation, and mortality far better than BMI does.

What to watch instead

Waist-to-height ratio — captures the visceral-fat redistribution that BMI misses. Still works well after 65; the target (keep waist under half your height) is the same.
Grip strength. A simple hand dynamometer reading; below ~27 kg in men or ~16 kg in women is a recognised sarcopenia indicator. Your GP or a physiotherapist can test this.
Gait speed. Walking speed over 4 metres; below 0.8 m/s is another sarcopenia and frailty marker.
Body fat % — useful if you suspect normal BMI is masking high fat. The Navy formula works reasonably in older adults, though accuracy is lower than in the general population.

When losing weight is (and isn't) a good idea

For older adults with BMI above 30 and metabolic complications (type 2 diabetes, hypertension, NAFLD), intentional weight loss still has benefits — but the goal should be preserving muscle, not just shrinking the scale number. That means:

Resistance training twice a week is non-negotiable during any weight-loss attempt. Without it, up to a third of lost weight is muscle.
Higher protein intake — typically 1.2–1.6 g per kg of body weight daily — preserves muscle during a calorie deficit.
Slow pace — 0.25–0.5 kg per week, not more.

For older adults in the “overweight” BMI range (25–30) with no metabolic problems, the evidence doesn't support intentional weight loss as a routine goal. Focus on strength, mobility, protein intake, and cardiovascular fitness instead.

Use the BMI calculator with older-adult context

The BMI calculator's Personalize result panel has an age-group option. Selecting “Older adult (65+)” adds the appropriate context to the result and softens the interpretation of BMI values in the 25–30 band. Pair it with the waist-to-height ratio, which remains a reliable risk signal at any age.

Measuring correctly

See how to measure your waist correctly — tape placement matters, and for older adults with posture changes or abdominal softening, getting the right landmark takes a moment of care.

Medical disclaimer. This article is for general educational use and is not medical advice. Weight-loss decisions in older adults should be made in partnership with a qualified healthcare professional, especially when managing chronic conditions. Unintentional weight loss at any BMI should be discussed with a clinician.