Research to date has convincingly demonstrated that nutrition impacts depression. Population based studies have shown that diet, food types, dietary supplements, gut bacteria, endocrine systems and obesity all play a role in depression. While nutrition could provide an important therapeutic opportunity in depression, clinical trials have not shown clinically meaningful results and it appears unlikely that nutrition is a central determinant of depression. Conversely, however, prior research is inconclusive to inferring that nutrition does not have a clinically significant effect. This would require elucidating precisely when nutrition affects depression which necessitates an alternative, more granular, model for the nutrition-depression interaction. The network theory of mental disorders, which studies how mental disorders arise from a causally related network of symptoms and external factors, is proposed as an alternative model for understanding the complexity of the nutrition-depression link. This approach would uncover which relationships, between aspects of nutrition and depression symptoms, warrant further study at a population and laboratory level. Furthermore, from within nutrition science, is a movement dubbed ‘New Nutrition Science’ (NNS) that aims to integrate biological, social and environmental determinants of nutrition. NNS is important to nutrition-depression research which has yet to reveal how social factors impact the nutrition-depression interaction. Network theory methodology is fully compatible with the network modelling already used in NNS. Embracing both network theory and NNS in future research will develop a full and complex understanding of nutrition in depression.