Type 1 diabetes (T1D) is a chronic metabolic disease, and currently there is still no cure. The focus of therapy is hence on optimal management of the disease, aiming for a healthy nutritional pattern, carbohydrate counting and favourable glycaemic control, to avoid the development of complications in later life. Finding the right balance is what works when it comes to nutrition and diabetes, and dietary knowledge has a direct impact on the dietary behaviour. Thus, it is important that dieticians are giving the right information and advice about a healthy diet to people with T1D, and identifying which patients need further education. However, analysing dietary composition and behaviour is incredibly challenging. The patients can falsely report, and they may alter their eating pattern. Therefore it is important that healthcare workers and dieticians receive correct information. The aim of this study was to investigate the relationship between diet composition, dietary behaviour, body composition, glycaemic control, and variability in patients with T1D; aimed to assist healthcare workers such as dieticians to improve diabetes treatment. Gaining more information on the impact of nutritional patterns on glycaemic control and variability is crucial. In this study cohort, there was excessive alcohol consumption and an insufficient intake of fibre and PUFA. The macronutrient distribution (%) was in line with the dietary guidelines, while the glycaemic control parameters were on the edge of the target values. Interestingly, higher intake of CHO was associated with more glycaemic variability on CGM.