Traditional subsistence foods, such as fish and marine mammals, and to a lesser extent shellfish, are the only significant direct dietary sources of two important types of the omega-3 fatty acids called eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA and DHA protect against heart disease and possibly diabetes. The replacement of a subsistence diet that is low in fat and high in omega-3s with a market-based Western diet has increased the risk of cardiovascular disease and diabetes in Alaska Natives. Many market (store-bought) foods are high in fats, carbohydrates, and sodium; and these may lead to increased weight gain, high cholesterol (hypercholesterolaemia), high blood pressure (hypertension), and chronic diseases.