As it turns out

there are many food day calendars.

Google works to turn up some interesting things, or start with this article:
http://www.huffingtonpost.com/2014/05/05/food-day-birthday-quiz_n_5266742.html

I must say that I don't want lemon meringue pie on my birthday, and I have much more respect for the calendar of food days at food.com http://www.food.com/food-holidays/julia-child-s-birthday-0815 which simply identifies it as also Julia Child's birthday.

But none of these calendars seem to capture the food days devoted to advocacy for a better food system.

Oh, here's one from the University of Nebraska food.unl.edu/fnh/seasonal-ideas that does weeks and months and gives a bit more info on them - except it has neither the national (October 24) or international (October 16) Food Day!