I was very low on food and my banana tree had some fruit. Brought my chief over to direct the harvest and accidentally placed him on the food bin. It said in the line something like Chief creating magic so I let him go for it. There was a sound of a gong and presto I had more food. That happened 3 times during this one incident for the total of about 300 food.
Follow up note: I just placed the chief on the food bin and it said he could only do it once every 24 hours.