And Heinz is just sugared tomato sauce so what's your point? (Hunt's is too though, and probably most others.)
As someone else pointed out, Whataburger isn't doing Heinz. And blech, McDonald's fountain is possible the worst of any fast food place (only worse soft drinks I think has been at Chili's where its like McDonalds but with extra bad flavor from their tastes like dipped in bleach glasses and probably never having their fountain cleaned). I figured McDonalds would have been the flagship for the "Freestyle" machines, but apparently not. Even Subway has those (although small ones that are quite limited, not even sure if they have the flavor options like cherry/etc). Their awful drink seletion and their beef flavor has really made McDonalds probably my least favorite burger place (I almost always get breakfast instead on the few times I eat there). In 'n Out isn't far behind (for similar reasons, but its way better value). Thankfully there's a bunch of places down here that have Pepsi (most of the nationwide burger chains have Coke which sucks, but there's a bunch of mom and pop or local chains with Pepsi here), and better burgers to boot (Culver's, better beef, waaaaaaay better cheese, and Pepsi fountain, they also have their own Root Beer; oh and better variety than McDonald's outside of breakfast).