The significance of BMI (Body Mass Index) in evaluating health lies in its ability to offer a quick estimate of body fat based on height and weight. While it serves as an initial screening tool to assess weight categories (underweight, normal weight, overweight, and obesity), it does not measure body fat directly. BMI can indicate potential health risks associated with higher body fat levels, such as cardiovascular diseases and diabetes. However, it should be considered alongside other factors for a comprehensive health evaluation.