According to this USDA report, some are not. They claim that sugary and sodium-laden foods, as well as animal protein, cost more based on their formula. Grains, fruit, vegetables, and dairy cost less. Fruits and vegetables could cost a lot less if we allowed more subsidies for them, or, abolish subsidies for Big Grain, and let the growers duke it out on a level playing field. The cost for animal protein would also cost less because if grains were more expensive to feed livestock, producers would be more apt to allow animals to eat what they are supposed to (i.e. grass-fed beef).