Final answer:
The nurse's best approach is to review the diet and provide evidence-based information about healthy eating patterns and behavior modifications.
Step-by-step explanation:
The nurse's best approach to educating a patient who wants to start a new popular weight loss diet is to review the diet and provide the patient with evidence-based information. The nurse should not blindly support the patient's decision without assessing the safety and effectiveness of the diet. Instead of providing a meal plan or encouraging the diet in addition to increased physical activity, the nurse should focus on educating the patient about healthy eating patterns and behavior modifications that promote sustainable weight loss.