This chapter, written for undergraduate medical students and post-graduate doctors in training, presents information on how to manage weight gain — a case which they are likely to encounter in the future in a general practice setting. It presents the case of a practice nurse who sought advice from the general practitioner about a 52-year-old diabetic woman who has come requesting sibutramine tablets to lose weight. She has known her for 5 years when the patient was referred to the nurse for weight loss having been diagnosed with pre-diabetes. The chapter provides details of the patients' medical history and the key findings of clinical examination, together with initial investigation results data for evaluation, and helps them develop their skills of clinical reasoning. Key questions then prompt the student to evaluate the patient, and reach a decision regarding their condition and the possible treatment plan.