Diet is largely considered to be a major factor in the occurrence of disease. The science of nutritional epidemiology involves evaluating the relationship between dietary and nutritional factors and disease and health outcomes. Findings from nutritional epidemiology studies play a key role in formulating dietary recommendations and guidance. However, Investigating the link between diet and health outcomes is complex and challenging, as it is difficult to disentangle the association between a food group, single food, or nutrient and disease risk. Thus, critically examining the underlying methodology is of paramount importance. EpidStat epidemiologists and health scientists have extensive expertise in research methodology and interpreting results from nutritional epidemiology studies.