Living with Diabetes

Insulin treatment and weight gain


Weight gainWeight gain is a common problem with insulin therapy and presents a major concern for many patients contemplating a change to insulin. In some instances this may pose a barrier to commencing insulin.

It is well recognised that poorly controlled diabetes is associated with loss of weight due to loss of glucose in the urine. Any form of treatment that substantially lowers blood sugar levels and thereby reduces loss of glucose in the urine, is likely to be associated with an increase in weight. This is simply due to the calories which were previously ‘wasted’, being absorbed; fat and muscle bulk is restored.

What are the potential problems associated with weight gain?

  • excessive weight gain may actually make blood sugar control more difficult
  • increased cardiovascular risk
  • weight gain in turn may cause resistance to the action of insulin which increases your requirement of insulin
  • reduced ability to exercise coupled with low mood which also impairs motivation

Will I put on weight if I inject insulin?

Intensive insulin treatment is associated with weight gain, usually in the order of 2-3 kg (4-6 lbs). This would be expected with most treatments which improve blood sugar control.

What are the reasons for weight gain?

A significant part of the weight gain associated with insulin treatment may simply be due to regaining weight lost due to uncontrolled diabetes. Continued weight gain is more likely related to lack of dietary restraint.

It is thought that some people on insulin, may snack frequently to avoid hypoglycaemia or in some cases regularly overcompensate for treatment of hypoglycaemia.

Tips to avoid putting on weight

Weight gain is often distressing and potentially harmful. The importance of diet and exercise in prevention cannot be over-emphasised. Plan a regular exercise program and stick to it. Regular exercise improves insulin sensitivity and you will achieve good control with a lower dose of insulin. See sections on diet and exercise for more advice.

In people with type 2 diabetes, combination with metformin can help curb unnecessary weight gain. Metformin may suppress appetite and also helps improve insulin sensitivity.

Avoid excessive doses of insulin which may lead to increased caloric intake. If your blood sugars are very tightly controlled you may be able to reduce your dose of insulin.

If hypoglycaemia is frequent, lower your dose of insulin rather than eat more to ‘keep your blood sugars up’.

Do some types of insulin cause less weight gain than others?

There is evidence from clinical studies that insulin detemir (LevemirR) which is a basal insulin analogue, may be associated with a reduced risk of weight gain when compared with isophane insulin.


Dr Nishan Wijenaike
Consultant Diabetologist
November 2004