I believe sculptures of overweight people would not pass easily as they would be considered offensive for real overweight people. Instead of that, how about making sculptures of junk food items showing their true ingredients? It would look like a 3D infographic in the shape of a hamburger, a coke, a packet of French Fries. For example, 40% fat, 30% sugar, 20% you cannot pronounce it, 5% water, 5% we don’t know. Ideally, they would be made of the actual ingredients in the right proportions (as Milos Stankovic mentioned fat would look disgusting). But as that would probably be impractical, they could at least be made to look like those ingredients.