BMI cutoffs were established for adults broadly — 18 to 65. For older adults, several large studies suggest the relationship between BMI and mortality is different than for younger adults, with the lowest-risk range shifted slightly higher.
What changes with age
Two physiological changes matter. First, sarcopenia — loss of muscle mass — accelerates after about age 60. Second, body composition shifts: more abdominal fat, less subcutaneous fat, less muscle, less bone density. A 75-year-old at BMI 24 likely has a higher body fat percentage than they did at 24 in their 30s.
What the research shows
Several large meta-analyses have found that for adults over 65, the lowest mortality risk sits in the BMI 25–27 range — the standard "overweight" zone. Being slightly heavier may be protective by providing reserves during illness and slowing sarcopenia.
This finding is well-established but contested. The U.S. Geriatrics Society notes that obesity (BMI 30+) is still associated with higher mortality and disability in older adults.
What older adults should focus on
Muscle and function matter more than weight. Grip strength, walking speed, and ability to rise from a chair predict outcomes better than BMI in this age group.
Unintentional weight loss is a red flag at any age but especially after 65. A 5% drop over 6 months without trying warrants a doctor visit.
Practical guidance
Track BMI as one trend line among several. Pair it with strength check-ins (can you carry groceries up stairs without effort?) and any unintentional weight changes.
Talk to your doctor about whether your individual BMI is in a healthy range for you. The standard cutoffs are statistical, not personal.
Try the free BMI Calculator
Free, offline, available in 20 languages on Android and iOS. 30 seconds is all it takes.
Google Play App StoreA free, fast BMI tracker still helps older adults notice trends. Our BMI Calculator takes 30 seconds and you can compare months at a glance.
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