There is limited understanding about eating behaviours or the reasons for the high rates of anxiety and depression in people with Coeliac Disease (CD). As prescribed dietary management is the only treatment for CD, and what we eat has been demonstrated to impact our mental wellbeing, CD treatment itself is anticipated to impact mental health. Increased dietary control may also cause people to be at an increased risk of disordered eating and adverse mental health outcomes. Understanding more about how dietary beliefs, behaviours and mental health outcomes interact is therefore crucial in supporting psychological wellbeing in this population. The overarching aim of this research portfolio was to understand how diet and dietary beliefs might impact mental wellbeing in females with CD and shed light on females’ experiences of CD in relation to this. Part one of this portfolio presents an empirical paper attempting to identify links between dietary intake, dietary beliefs and mental health outcomes in women aged 18-25 with CD. Findings indicate that females with CD have a suboptimal nutritional intake and that consuming more fats and having higher overall energy intake was associated with more adverse mental health outcomes.  Part two of this portfolio includes an empirical paper which aimed to understand what might influence dietary choices in this population. Three themes were identified as being central to understanding women’s experiences of CD in relation to their dietary choices: negotiating uncertainty in CD; CD related burnout; and a sense of alienation/ separation from others. People described eating more prepackaged gluten free foods due to feelings of exhaustion, avoiding social events that may contain food due to gluten related threat, or consuming food that may be contaminated by gluten in a desire for social inclusion. Findings highlighted the importance of increased dietary and psychological support for females with CD as well as an increased awareness of CD in the general population. Further research in this area with a larger and more representative sample of the global majority is advised.