Loss of weight can be a sudden symptom of type 1 diabetes and can typically lead to a loss of muscle mass in type 2 diabetes.


Possible causes of a sudden and unintentional loss of weight include:

  • Diabetes
  • Addison’s disease
  • Celiac disease
  • Cancer
  • Depression
  • Overactive thyroid

When to see your doctor

It is important to see your doctor if you have unintentionally lost a significant amount of weight – 10lbs (4.5kg) or 5% of your body mass within 6 to 12 months.

If a child is slow in putting on weight, this could indicate type 1 diabetes, particularly if other symptoms of diabetes are present.

Weight loss and type 1 diabetes

Sudden loss of weight, or failure to gain weight in children, can be one of the more noticeable signs of type 1 diabetes.

When the body cannot produce enough insulin, this prevents the body getting glucose from the blood into cells. To compensate, the body will break down fat and protein to produce ketones, an alternative source of energy.

Sudden weight loss in diagnosed type 1 diabetes, can be brought on by deliberate omission of insulin injections. This is known as diabulimia and can greatly increase the chance of developing long term diabetes complications at an early age.

Weight loss and type 2 diabetes

Loss of muscle mass is a relatively common sign of type 2 diabetes and should prompt a visit to your doctor to get a diagnosis.

Dramatic loss of weight can also occur in people diagnosed with diabetes if the body significantly loses its ability to produce insulin.

Your health team should measure your A1c at least once a year and pick up on any rises in blood sugar levels which can then be treated.