People with diabetes experience sudden weight loss, as inadequate insulin hampers the body from obtaining glucose from the blood to be used as energy in the body's cells, according to Diabetes.co.uk. This makes the body burn fat and muscle for energy, which reduces a person's body weight.
Unexpected weight loss commonly occurs before a diagnosis of type 1 diabetes, although it can also affect people with type 2 diabetes, notes Diabetes.co.uk. Dr. Kimberly Buss, a diabetes specialist of the Sutter Medical Foundation, explains that uncontrolled diabetes leads to weight loss by causing the body to lose extra calories by adding sugar into the urine. When the blood sugar level increases, the body fails to reabsorb all of the sugar that the kidney naturally filters. The sugar then goes into the urine, often causing people with high sugar levels to urinate frequently and become extremely thirsty. People with these symptoms often suddenly experience significant weight loss. They also tend to drink sugary drinks due to extreme thirst, raising their sugar levels even higher and causing more severe weight loss.
Dr. Buss notes that anyone who suddenly develops sudden, considerable weight loss, particularly when accompanied by extreme thirst and frequent urination, must see a health care provider to get diagnosed.