as one of my very insightful small business friends likes to say "under capitalism all food tends to fat, sugar and salt".

these are the taste experiences we crave and enjoy (salt is a bit different - its very bitter by itself, but has massive positive impacts on our appreciation of *other* flavor). coca cola and mcdonalds, for all the utter crap that they peddle, have created products that manage to appeal to these cravings. of course, it can be done much better, but they're in the business of doing it well enough, for less money. although marketing has undoubtedly played a role, i'm sure you could have spent the same amount as both of them combined to sell arugula salad with roast beets, goat cheese, roasted walnuts and a blackberry balsamic dressing and gone precisely nowhere. although hmm, that does sound pretty good ...