I saw a food photographer explain that for soup they used to put marbles in the can to push up the meat/vegetables and they aren't allowed to do that any more.

I saw a food photographer explain that for soup they used to put marbles in the can to push up the meat/vegetables and they aren't allowed to do that any more. But they can (and do) pick through cans to find the biggest and best pieces since it's stuff that was actually in the can. It's an interesting exercise in dancing just on this side of the line.