If you're not obese and you've lost more than 10 percent of your body weight during the past six months — for instance, 15 pounds (7 kilograms) if you weigh 150 pounds (68 kilograms) — consult your doctor.
An unexplained drop in weight could be caused by various conditions — including overactive
thyroid (hyperthyroidism),
diabetes, depression,
liver disease, cancer or disorders that interfere with how your body absorbs nutrients (malabsorption disorders)...Consult nearest physician they will do the needful.