Which client should the nurse assess for malnutrition?

The correct choice is the adolescent client following a fad diet because this demographic is particularly vulnerable to malnutrition due to potentially restrictive eating patterns and inadequate nutritional intake. Fad diets often eliminate entire food groups or excessively limit caloric intake, leading to deficiencies in essential vitamins, minerals, and macronutrients. Considering the adolescent's growth and development needs, coupled with the lack of essential nutrients from a poorly balanced diet, there is a significant risk for malnutrition.

In contrast, while hypertension can lead to dietary modifications, it does not directly imply malnutrition. A client recovering from hip surgery may experience temporary changes in appetite or nutrition needs, but they generally do not face the same risk unless prolonged recovery occurs with inadequate nutrient intake. A client with a mild sore throat might have a reduced appetite but is unlikely to be assessed for malnutrition without more significant weight loss or prolonged symptoms affecting intake. These factors highlight why assessing the adolescent client on a fad diet is critical in identifying the risk of malnutrition.