Ultra-processed foods are highly processed, industrial formulations that are made mostly from substances extracted from foods, nonculinary ingredients, and cosmetic additives whose purpose is to make the final product convenient, hyperpalatable, and highly profitable. The consumption of ultra-processed foods has rapidly increased worldwide. Studies have shown that high intake of ultra-processed foods is associated with an increased risk of type 2 diabetes. Among individual ultra-processed subgroups, processed meats, ready-to-eat or -heat dishes, and sugar- and artificially sweetened beverages are associated with an increased diabetes risk, whereas yogurt and ultra-processed whole-grain breads and cereals are associated with a reduced risk, suggesting that the composition of ultra-processed food (e.g., relative contributions of processed meats vs. ultra-processed cereals to the total ultra-processed food intake) may be relevant to the disease risk. Poor nutrient profile, shorter chewing time, faster digestion, and lower satiety of ultra-processed foods can unfavorably influence cardiometabolic health. Some non-nutritional factors, such as food additives and contaminants, are also known to disrupt gut microbiota and promote insulin resistance and inflammation. The growing evidence suggests the degree of food processing, in addition to diet quality, to be considered as a criterion to identify a healthy diet. Public health measures are required to create a healthy food environment that promotes consumption of high quality, unprocessed or minimally processed foods.