The purpose of this survey is to report experiences with variants of a ketogenic diet in a group of individuals diagnosed with McArdle disease (glycogen storage disease type V). Further more the survey will report on physical activity, fatigue, sleep and quality of life in this cohort.

Currently, there is no satisfactory treatment for McArdle disease. The limitation in people with McArdle disease is due to a limited availability of energy in the muscle due to affected carbohydrate metabolism. A key element in improving muscle function is therefore to introduce alternative energy sources. Ketone bodies are a well-known source of energy for both brain and muscle. Ketone bodies are produced during fasting or when following a ketogenic diet. A ketogenic diet is a diet high in fat and low in carbohydrates. The classic ketogenic diet contains up to 90% fat, but there are several alternative diets with less fat, including a modified ketogenic diet, Atkins diet, LCHF (low carb high fat), OMAD (one meal a day) and more. This survey will collect information on all variations. The rationale for a ketogenic diet for persons with McArdle disease makes good sense in theory, as the diet would contribute with a new source of energy (ketone bodies) independent of the affected carbohydrate breakdown. However, evidence is sparse on whether the diet actually works. The primary purpose of this survey is to report experiences with variants of the ketogenic diet in a group of individuals diagnosed with McArdle disease. Secondarily this survey will collect information on physical activity, fatigue, sleep and quality of life in this cohort

Inclusion Criteria:

• Verified GSDV diagnosis

Exclusion Criteria:

• Age under 18 years

McArdle disease