Pepsi was supposed to be an after-iftar digestive drink! What happened is that, with time, it moved up the food chain (no pun!) to become part of the meal itself hence becoming part ot of the menu. Also here is a fun fact, the large size referred to in the ad is actually 1 liter which is smaller than today's "standard" large 1,25 liter.
One wonders if ice cream will become part of dinner too....