The trick is to care less. Whether intentionally or not, you have turned this into a battle of wills. The rule is eat or don't. People who choose to eat it get a small treat after dinner those that don't, don't. It's not up to you, it's just the rule. See? Don't you already care less than you did? No kid that is being offered good food on a regular basis has ever starved to death. They'll eat when they're hungry.