Ethical management of obesity screening in schools involves several key practices to avoid stigmatization. Firstly, ensuring confidentiality is paramount. Information about students' BMI or obesity risk should be handled discreetly and shared only with parents and healthcare providers as necessary. Secondly, screenings should be conducted in a non-judgemental, respectful manner, with clear communication about the purpose and importance of the screening. Thirdly, education about healthy lifestyles should be inclusive and positive, focusing on overall well-being rather than weight alone. Finally, involving students in discussions about health and nutrition can help create a more supportive environment, reducing the stigma associated with obesity.

Misclassifying individuals using BMI can lead to several consequences. For individuals wrongly categorised as overweight or obese, there can be unnecessary psychological stress, stigma, and potential body image issues. This might also lead to unnecessary medical interventions or dietary changes. Conversely, individuals with high body fat but normal BMI might be overlooked and not receive needed advice or intervention for reducing health risks associated with obesity. Misclassification can skew public health data, affecting the allocation of resources and the focus of health interventions. Accurate classification is crucial for individual health management and for informing public health policies and strategies.

The waist-to-height ratio (WtHR) can be used alongside BMI to provide a more accurate assessment of obesity-related health risks. This ratio is calculated by dividing waist circumference by height, and it offers an insight into the distribution of body fat, specifically central or abdominal fat. A WtHR of 0.5 or higher is generally considered indicative of higher health risks, regardless of BMI. Using WtHR in conjunction with BMI allows for a more nuanced understanding of an individual’s health status, identifying those who may not be classified as obese by BMI alone but who carry a significant amount of harmful abdominal fat.

BMI continues to be widely used due to its simplicity, cost-effectiveness, and the ease with which it can be applied to large populations. Calculating BMI requires only two basic measurements – height and weight – making it feasible for use in various settings, including clinics, schools, and large-scale epidemiological studies. Despite its limitations, such as not differentiating between fat and muscle mass, BMI provides a general indication of weight categories (underweight, normal, overweight, obese) which are useful for initial health assessments. Moreover, it serves as a standardised metric, allowing for consistent comparisons and tracking of obesity trends over time and across different populations.

Waist girth measurement is a crucial complement to BMI in obesity assessment because it provides specific insight into the distribution of body fat, particularly abdominal fat. Abdominal fat, or central obesity, is a significant risk factor for metabolic syndromes, cardiovascular diseases, and type 2 diabetes, which BMI alone might not adequately indicate. By measuring waist circumference, health practitioners can identify individuals who may have a normal BMI but a high concentration of abdominal fat, thereby categorising them into a higher risk category. This dual approach of using both BMI and waist girth allows for a more comprehensive assessment of an individual's obesity-related health risks.