Nutritionist: The food pyramid was amended to provide the public with a healthier nutrition plan to combat the obesity epidemic. The base of the previous food pyramid -- the grains group -- advised people to eat six-to-eleven servings of pasta and bread per day. In contrast, the updated pictorial nutrition guide shows a plate, and it reduces the percentage of dietary intake of grains and replaces the difference with lean proteins and vegetables. The updated guide has been wildly successful, as citizens have lost a significant amount of weight. Which one of the following, if true, most strengthens the nutritionist's conclusion? ['Since the publication of the updated food guide, citizens have started to exercise more.', 'Eating more lean proteins and vegetables contributes to weight loss.', "Eating six-to-eleven servings of pasta and bread increased citizens' risk of heart disease.", 'The old food pyramid used horizontal layers, while the updated guide uses vertical layers.']