Does God eat the food you have placed before Him? He doesn’t. If we offer to Guru, the same way, he also doesn’t consume it all. He distributes to all of us.
Why then are we following this tradition of showing the food to God before consuming? It is out of gratitude!
We are grateful to God for giving us the ability to put in the effort to earn our food, we place before Him the food before we eat it.
(Q&A, USA, 29 Jul 2011)