Why is EVERYTHING in America HUGE?

Things here are bigger, but I doubt our houses are x4 the size of the houses in the UK. I believe it was yesterday I went to a 7/11 and bought a "Macho" sized fountain drink for $2.30 and it was almost as large as one of those 2 liter sodas you buy at grocery stores. Also, at KFC they will literally sell you a gallon of A&W Root Beer through the drive through.