How can physical food give life to the spirit? (which isn’t.) The answer is, that when we say blessings for the food, as the food itself is comprised of the words of God, the Divine letters (see Shaar Hayichud Vehaemunah, the second book of Tanya) that are constant Divine energy – hence these letters then get activated by the Divine energy – now of-course the soul is already Divine energy, hence the two meet up (like fire to fire.) The Baal Shem Tov gives a beautiful parable – once there was a king that lost a precious diamond, now before the king were minsters, soldiers and in general the people, who all loved him – he could have asked any of them – however he wished to give the reward for finding this – the ability to be proud of and brag about – to his only son; – now in essence, the king actually hid this diamond! his entire purpose was to be able to give the merit of finding it to his son (similarly, God took these original Divine sparks, for we know from the “body of Adam” there were sparks of Divinity within foods and he sent his special son the Jewish people to make blessings thereby elevating these sparks – this in truth is a great secret, for all physical things we encounter, as we use them for spiritual purposes (or say thank-you for them) we elevate them.)