In GLIM criteria, what BMI threshold is considered low for adults younger than 70 years?

• A. < 20 kg/m2
• B. < 22 kg/m2
• C. < 18.5 kg/m2
• D. < 25 kg/m2

Answer: (A)

GlIM uses low BMI as one of its phenotypic criteria for malnutrition, with age-adjusted cutoffs to reflect changes in body composition with aging. For adults younger than 70 years, a BMI below 20 kg/m² is considered low. This threshold helps identify individuals whose nutritional risk is not captured by weight alone but is evident through reduced body reserves. For adults 70 years and older, the threshold is lower in the sense that BMI below 22 kg/m² is the criterion, acknowledging age-related shifts in body composition. The other numbers—18.5 kg/m² is the general underweight cutoff in some guidelines, and 25 kg/m² is the threshold into overweight—do not define the GLIM low BMI criterion for younger adults.