Dietary and nutritional parameters are investigated in relation to disease occurrence at a population level in nutritional epidemiology. Nutritional epidemiology is a relatively young topic of medical research that looks into the link between food and health. It's a relatively new field of epidemiology that's becoming increasingly relevant to today's health issues. Diet and physical activity are difficult to adequately assess, which may explain why nutrition has received less attention in epidemiology than other risk factors for disease. Nutritional epidemiology applies nutritional science information to better understand human nutrition and explain fundamental underlying principles. Nutritional epidemiological research and interventions, such as clinical, case-control, and cohort studies, are also based on nutritional science knowledge. To investigate the link between diet and disease, nutritional epidemiology methodologies have been created. Nutritional epidemiology is becoming more interdisciplinary as genetic risk variables are included in causation models.