Okay, I've got a crazy idea. Why not create a combination of words that expresses the thing, instead of these very weird and incomprehensible-at-first-glance icons?

For example, for proteins: the word "protein" is understandable in English, French, Spanish, Italian, Portuguese, Greek and Swedish. The Russian "belok" should be understandable to Polish and Russian speakers, and the Dutch "eiwitten" should be understandable to Dutch and German speakers. Thus, writing "protein/belok/eiwitten" would be understood by almost everyone. "kcal" is even simpler and should be understood by almost everyone everywhere - maybe make it "kcal/calories" for more readability. "salt/sol/αλάτι" should cover everybody as well. Perhaps throw in the Cyrillic as well if McDonalds expects a large amount of uneducated Russians in their restaurants.

You could even put the native language in front to prevent any insult to cultures. Am I crazy, or might this actually work?