it’s an interesting subject, but as i started with the older grimoires which recommended fasting entirely (often for rather long periods), i don’t have much experience with an actual “magical” diet.
that’s not to say that i followed the grimoires and fasted as they recommend (in that i have a reasonably active life and i need to maintain my blood sugar levels out of necessity), but i tried to fast for at least the day of a working, which usually fell on a saturday.
these days i try and eat a little healthier in the morning (like a decent high fibre cereal) and i’ll fast from noon until well past midnight when i perform my workings. overall, my diet is terrible and i should know better, but i love my fast food, soda pop, cigarettes and the like. i generally won’t eat fruit unless it’s in cereal or with ice cream, so yes, i can attest to diet making a difference when it comes to ritual.
i should point out, though, that i’ve only noticed a difference of fasting a little vs not fasting, and not necessarily healthy food vs fasting or vs unhealthy food, because i don’t usually eat healthy food so i don’t have a frame of reference.
i have noticed that if i eat a nutritious, well-balanced meal (like camping food which is really convenient as i’m a college student right now) the night before, i have enough energy for the next day’s fast without it being too heavy.
it makes sense from a purely nutritional standpoint, though. we all know that bad food is bad for us (no matter how good it tastes:) and that it’s harder to run our bodies efficiently on high salt/fat/sugar diets compared to simply giving it what it wants and needs (fibre, simple sugars, complex carbs, proteins, essential fats etc). after fast food, i feel absolutely horrible, but i eat it because i like it at the time. if i wanted to train athletically, i’d definitely eat better simply because fast food would be a hindrance.
as the brain is just another organ of the body at the end of the day, it’s reasonable to suspect it wouldn’t operate any more efficiently than the other organs when fed poor quality food (or even just too-much food in one sitting).
just my humble hypothesis.
kind regards, james.