Thank you for the query. Diabetes mellitus (specially uncontrolled) can indeed lead to weight loss. Diabetes is a condition where there is deficiency of the hormone Insulin in the body. Insulin is an anabolic hormone (positive metabolism) and its deficiency leads to a catabolic state (negative metabolism). Insufficient insulin prevents the cells in the body from getting glucose (source of energy) from the blood (the glucose level in blood is thus increased). In an attempt to obtain energy,the body starts using up fat and muscle (i.e.protein) for energy. This leads to a reduction in body weight and loss of muscle mass. Whenever, there is a loss of body weight in a diabetic, it implies that the sugar is poorly controlled and the patient is in an insulin deficient state. The person in question (48 yrs old gentleman) has lost 30 lbs of weight in a span of 1.5 months, and he has other symptoms of diabetes (frequent urination, increased thirst), so he definitely has an Insulin deficient state in the body. Please recheck his blood sugar profile (Fasting blood sugar, Post prandial blood sugar and HbAic). He may need to start on oral Anti-diabetics or Insulin. Ofcourse dietary modifications are very important. Please visit the treating physician, who can perform a thorough check up (and rule out other causes of weight loss) and set up a management plan. Hope this helps you. Regards, Dr. Ayusmati Thakur