We just know that the process works and that we cooperate with it by eating. If we choose to eat nourishing food, the results are even better.
فَكُلُّ مَا نَعْرِفُهُ هُوَ أَنَّ هذَا مَا يَحْدُثُ حِينَ نَأْكُلُ .‏