Anorexia nervosa is a serious psychiatric disorder with high morbidity and mortality rate. Evidence for the optimal psychopharmacological approach to managing the disorder remains limited, with nutritional treatment, focused on weight restoration through the consumption of high energy diet, regarded as one of the fundamental steps in treatment. The human gut microbiome is increasingly recognised for its proposed role in gastrointestinal, metabolic, immune and mental health, all of which may be compromised in individuals with anorexia nervosa. Dietary intake plays an important role in shaping gut microbiota composition, whilst the use of fermented foods, foods with potential psychobiotic properties that deliver live bacteria, bacterial metabolites, prebiotics and energy, have been discussed to a lesser extent. However, fermented foods are of increasing interest due to their potential capacity to affect gut microbiota composition, provide beneficial bacterial metabolites, and confer beneficial outcomes to host health. This review provides an overview of the role of the gut microbiota in relation to the disease pathology in anorexia nervosa and especially focuses on the therapeutic potential of fermented foods, proposed here as a recommended addition to the current nutritional treatment protocols warranting further investigation.