The aim of this study is to analyse the effect of a diet with a moderate amount of carbohydrates and compare it with a traditional diabetic diet with a higher content of carbohydrates on mean glucose level, high and low glucose levels, and the risk of ketoacidosis in patients with type 1 diabetes. The glucose levels will be measured by blinded continuous glucose monitoring (CGM).

The trial has a cross-over design and 12 weeks in duration, where patients will be randomized to; 1) a diet with moderate carbohydrate content for 4 weeks and 2) a traditional diabetes diet for 4 weeks and with a wash-out period between for 4 weeks. The two diets will both be healthy and planned by a dietitian. There will be 50 subjects included in the study.

Inclusion Criteria:

• Type 1 diabetes
• Adults 18 years or older
• Written Informed Consent
• HbA1c ≥ 58 mmol/mol (7,5 % DCCT standard)

Exclusion Criteria:

• Pregnancy or planned pregnancy for the study duration
• Severe cognitive dysfunction or other disease, which is judged by the physician to be not suitable for inclusion
• Problems with compliance to the intervention diets (excluding a lot of the foods that are common in the diets like wholegrain/beans/lentils/fruit/vegetables) because of personal preferences, other diseases, stomach problems etc.
• Diabetes duration < 1 year
• Planned change in diabetes treatment (eg. Start with insulin pump, CGM etc.) during the study period
• Other investigator-determined criteria unsuitable for patient participation