Acromegaly is caused by a tumour located at the base of the brain in the pituitary gland that produces too much growth hormone (GH). Symptoms caused by the excess of GH, and consequently increased insulin like growth factor 1 (IGF-1), are disproportionate growth of body parts, fluid retention, snoring and excessive perspiration. The various metabolic changes that occur due to acromegaly increase the risk for insulin resistance, diabetes mellitus, arterial hypertension, sleep apnoea and thus an increased risk of cardiovascular disease if left untreated. The result is signs and symptoms, increased mortality, morbidity, and greatly reduced quality of life (QoL). Normalisation of GH and IGF-1 gives a normalisation of mortality, however morbidity and QoL do not (completely) normalise. After surgery, a somatostatin analogue is the primary medical treatment, however, normalisation occurs in only 40% of patients. Recently, in a proof-of-principle study, the researchers showed that a 2-week ketogenic diet (low in carbohydrates) in patients with somatostatin analogues could significantly reduce IGF-1 values. Patients felt better and sometimes even needed less somatostatin analogues. This proof of concept led to the new hypothesis that acromegaly patients with somatostatin analogues should possibly be treated with a eucaloric low-carbohydrate ketogenic diet for a longer period of time to improve their biochemistry, symptoms and QoL. Additionally, this diet can make a significant contribution in the treatment of insulin resistance and glucose intolerance that often occur in this patient group.