Despite the seeming innocence of the act, we’re warned by the Torah not to eat certain foods. But eating the wrong things wouldn’t be like stealing or like having illicit relations, so why the clamor? we wonder. (Though of course when a doctor warns us about our diet we tend to be rather “religious” about what we’re told, but that’s beside the point.)
In part it comes to the fact that food is so common, is healthy often enough, and is so downright essential, that we’d need to acquiesce to restrictions of it if we’re ever to prove our good intentions, for one thing. But also because foods actually “enter into your body and become your very flesh” as Ramchal offers, with the implication that it then affects your immortal soul attached to that flesh (suggesting of course that the expression “You are what you eat” goes far more than skin-deep).
And we’d need to be cautious as well because, as Ramchal puts it, “the heart is easily drawn to good food” even though forbidden, because we’d lose money when accidentally buying forbidden things (which is always a bother), and because of all sorts of other problems.
He makes yet another point, though. Basing himself on traditional sources he says that eating “forbidden foods actually cause spiritually unclean elements to enter into your heart and spirit,” to the point where “the Holiness of G-d is removed and drawn away from you” as a result. The effect of that is referred to as the “stupefaction” of the human heart (see Yoma 39a). And as a result of it “the true knowledge and sense of understanding that G-d gives to His holy ones … will be withheld from you”.
Let’s go into the details now.
There are certain “foods that are inherently forbidden” like pig and lobster, others “that are forbidden because they’re accidently combined with forbidden food” as when a piece of un-kosher meat is mistakenly placed in an otherwise kosher dish, and then there are other problematic details like “mixtures of meat and dairy, forbidden fats, blood” and more.
But what are we to do to avoid the problem? Ramchal suggests a sort of re- framing of the issue. “A thinking person”, he offers, “would consider forbidden foods ‘poison’ or as mixed with poison.” And after all, “if you were sure or even suspected that a piece of food was poisoned, would you eat it? Certainly not. You’d be a fool to.” So, “that’s how it should be when it comes to forbi dden foods which … are poisons to the heart and soul”. You should be off put by the very thought of eating it.