Anti-social cat and puking!?

I have two cats one is a 4 year old tabby and the other a 1 1/2 year old tabby. I was having issues with puking and found out that it was my younger cat overeating and puking his food. So I attempted to separate the feedings but my other tabby WILL not come out of hiding to feed. He wants to wait till no one is around and will run off if I try and watch them eat to make sure each is eating the correct amount. But if I leave the food down the younger cat will eat all of it and puke it all back up through out the house go back and then get his tummy full again. Both are healthy and vet checked for no physical issues. How do I get my cat over the fear of me (his only issue is with me) and be able to watch my piggy younger cat. I'm just worried that the older cat just isn't eating the amount he should be.