BMIbased

BMIbased is an adjective used in medical, research, and policy contexts to describe approaches that rely on body mass index (BMI) as the primary metric for assessment, decision-making, or categorization. The term is a descriptive label rather than an official diagnosis, applied to methods that implement BMI thresholds to define risk groups, determine eligibility for services, or guide the level of intervention.

Common applications include clinical guidelines that set treatment eligibility for obesity or weight-management programs at BMI thresholds (for example, BMI ≥ 30 kg/m2, or BMI ≥ 27 with comorbidities). In research, BMI-based stratification divides participants into weight classes to compare outcomes. In public health, BMI-based surveillance tracks the prevalence of overweight and obesity and monitors trends over time.

Calculation and categories: BMI is weight in kilograms divided by the square of height in meters. WHO categories typically classify BMI as underweight (<18.5), normal weight (18.5–24.9), overweight (25–29.9), and obesity (≥30). Children use BMI-for-age percentile cutoffs. BMI-based rules are often simplified for ease of use, especially in resource-limited settings.

Limitations and considerations: BMI does not distinguish between muscle and fat and can misclassify muscular individuals. It may vary with age, sex, and ethnicity, and BMI-based decisions can overlook metabolic health despite normal BMI, or vice versa. Critics argue for incorporating additional measures such as waist circumference, body composition, or cardiometabolic risk factors, and warn against stigmatization.

Despite limitations, BMIbased methods remain widely used due to simplicity, low cost, and their role as a common reference point across healthcare systems for large-scale comparisons.