A healthy diet is a diet that helps to maintain or improve overall health. A healthy diet provides the body with essential nutrition: fluid, macro-nutrients, micro nutrients, and adequate calories. For people who are healthy, a healthy diet is not complicated and contains mostly fruits, vegetables, and whole grains, and includes little to no processed food and sweetened beverages. The requirements for a healthy diet can be met from a variety of plant-based and animal-based foods, although a non-animal source of vitamin B12 is needed for those following a vegan diet. Various nutrition guides are published by medical and governmental institutions to educate individuals on what they should be eating to be healthy. Nutrition facts labels are also mandatory in some countries to allow consumers to choose between foods based on the components relevant to health. A healthy lifestyle includes getting exercise every day along with eating a healthy diet. A healthy lifestyle may lower disease risks, such as obesity, heart disease, type 2 diabetes, hypertension and cancer. There are specialised healthy diets, called medical nutrition therapy, for people with various diseases or conditions. There are also prescientific ideas about such specialised diets, as in dietary therapy in traditional Chinese medicine