i was always told they will eat when they r hungry just keep him away from all junk food or treats that what i did with my 3.5 yr old now i just leave carrots and fruit in the fridge were she can reach it and i make what i know she will eat for lunch at least i know she is eating something. p.s. she loves carrots and peanutbutter try cutting his food into shapes or have him help when you cook my daughter does alot better when she helps