For seniors, BMI interpretations shift. A slightly higher BMI is often linked to better health outcomes and longevity in older adults.
Research suggests that the standard BMI "Normal" range of 18.5 – 24.9 may not be appropriate for people over 65. For older adults, being underweight is a significant risk factor for frailty and bone loss. Therefore, medical experts often use a shifted scale:
| Category | BMI Range (Over 65) |
|---|---|
| Underweight | Less than 22.0 |
| Normal / Optimal | 22.0 – 27.0 |
| Slightly Overweight | 27.1 – 30.0 |
| Obese | More than 30.0 |
The "Obesity Paradox" describes the finding that being slightly overweight (BMI 27-30) in old age can actually lead to a lower mortality rate than being "Normal weight." This occurs because extra fat provides a safety margin and energy reserve during illness or recovery from surgery.
A BMI below 22 in seniors is strongly correlated with Osteoporosis, increased risk of fractures, and malnutrition. It is often more critical for seniors to focus on maintaining muscle mass (via resistance training and protein intake) than on losing weight.