“To be healthy, diets must have an appropriate calorie intake and consist of a variety of plant-based foods, low amounts of animal-based foods, unsaturated rather than saturated fats, and few refined grains, highly processed foods, or added sugars. The food group intake ranges that we suggest allow flexibility to accommodate various food types, agricultural systems, cultural traditions, and individual dietary preferences – including numerous omnivore, vegetarian, and vegan diets,” says co-lead commissioner Walter Willett from Harvard University.