A nurse is caring for a patient who has a body mass index (BMI) of 18. The nurse should place the patient in which of the following BMI categories?

Choice A rationale Obesity is defined as a BMI of 30 or greater. A BMI of 18 is significantly below this threshold. This category indicates a high level of body fat, which increases the risk for various chronic diseases such as heart disease, type 2 diabetes, and certain cancers. The patient's BMI does not fit this classification. Choice B rationale Overweight is defined as a BMI between 25.0 and 29.9. The patient's BMI of 18 is substantially below this range. This category indicates excess body weight relative to height but is not classified as obese. Individuals in this category are at an increased risk for health problems. Choice C rationale Underweight is defined as a BMI below 18.5. The patient's BMI of 18 falls directly into this category. Being underweight can be a sign of malnutrition or an underlying health issue and can lead to its own set of health problems, including weakened immune system, osteoporosis, and anemia. Choice D rationale Healthy weight is defined as a BMI between 18.5 and 24.9. The patient's BMI of 18 is just below this range. This category is associated with the lowest risk for weight-related health issues and is considered the standard for good health. The patient's BMI is not within this range.