Religious people have created an idea of God that gave them the self-elected power to be the voice of God. Having this foundation, they can now declare that whatever they say, do or receive is ordained by God Almighty. And the only option we have in this instant is to either believe them or disbelieve them, but we cannot prove their claims to be wrong. Well… at least, that is what they think. According to their strategy, the only way anyone would be able to disprove their convictions is by summoning God to verify these claims. They know that is not going to happen, and as long as God remains absent they are left free to make any false claims they choose to without fear of accountability.
Fortunately, we do not need the materialized presence of God to verify any of their claims. We have our own system of accountability to prove whether or not these claims they make are truly ordained by God Almighty.
If God is all good, then such a pure entity will not offer anything in the nature of kindness that will inflict harm upon us. Bearing this in mind, we can also all agree that God will not offer poison to anyone to eat. Since we all know this, direct validation from God is no longer necessary. All we have to do now is to prove if what people have said is ordained by God is poisonous or supportive of their spiritual, mental and physical health.
Religious people like to bow their heads and thank God for their meal before eating it. Saying "thank you" let us know that they acknowledged their food as a gift from God. Given the provided system of verification, we can use it to determine if their food is from God or is only by virtue of their own personal will. If it is poisonous, we will know absolutely that it is not from the God of Nature; maybe their God, or some other God. And if their God did feed them poison then it lets us know that such God isn’t really catering to their best interest (hates them).
Some of the common "foods" that religious people credit their God for, which are actually poisonous to the body, include: dairy, white rice, white flour, meat (chicken, swine, beef, lamb, etc.), liquor and many others. So, when they give thanks for these types of food they are literally giving thanks for poison.
Please note: this system of validation is not only limited to diet, it applicable to everything.