A client is receiving orlistat as part of a weight management program Which ongoing assessment should be included in the plan of care to determine the effectiveness of the medication

Orlistat is a lipase inhibitor used for weight management that works by blocking the absorption of approximately one-third of dietary fat consumed. Because the medication's mechanism directly reduces fat absorption to limit caloric intake and promote weight loss, the most meaningful indicator of its effectiveness is a change in body mass index (BMI), which reflects actual changes in the client's weight relative to height over time. BMI is the standard clinical measure used to track the progress of obesity treatment. Serum protein levels would be relevant if there were concern about nutritional deficiencies, but are not the primary effectiveness measure for this medication. Depression screening is important as a baseline and ongoing assessment because obesity and weight management challenges can affect mental health, but it measures psychological wellbeing rather than the drug's pharmacological effect on weight. Daily calorie count tracks dietary intake and is useful for general dietary management, but it does not directly measure the drug's effectiveness in producing weight loss; a client could reduce calorie intake without losing weight. Therefore, BMI is the most direct and objective measure of whether orlistat is achieving its intended therapeutic outcome.