The Atkins Nutritional Approach, popularly known as the Atkins Diet or just Atkins, is the most marketed and well-known of the low-carbohydrate diets. The Atkins Diet represents a radical departure from prevailing diet theories. Atkins claimed there are two main unrecognized factors about Western eating habits, arguing firstly that the main cause of obesity is eating refined carbohydrates, particularly sugar, flour, and high-fructose corn syrups; and secondly, that saturated fat is overrated as a nutritional problem, and that only trans fats from sources such as hydrogenated oils need to be avoided. Consequently, Dr. Atkins rejects the advice of the food pyramid, instead asserting that the tremendous increase in refined carbohydrates is responsible for the rise in metabolic disorders of the 20th century, and that the focus on the detrimental effects of dietary fat has actually contributed to the obesity problem by increasing the proportion of insulin-inducing foods in the diet.