This food actually affect summoning magic skill up,while using food at least you see skill up,whitout you see a .1 after a couple hours lol.so definitely it works,from what i have seen.
Wonder why they add this. Possible reasons I can think of are:
1) This will affect both offensive and defensive magic
2) This will work on skills that didn't benefit from magic skillup food before (Summoning and BRD ones)
3) Previous food have a "cap", after you reach a certain level of skill they stop working, this food will work beyond that cap
I haven't tested this food, or seen any information posted on it; sorry if I'm late and wrong, but I was thinking we already have melee and magic skillup foods, what if this is for synthesis skills? Just throwing a theory out there in case anyone gets bored enough to test it.