It sounds like he's regurgitating his food - basically the food goes into the gullet, but is brought back up before it gets to the stomach. If this has hapenned since he was born it is likely to be a condition called megaoesophagus - where the oesophagus (gullet) is wider than normal.
Try feeding your cat very small amounts of food at a time, and raising it off the floor may help (although many cats will take the food down to floor level then eat it there!).
Let us know how you get on.