Recent research from around the world shows that childhood obesity leads to greatly increased adult disease. As a parent, who is knowingly making your children obese, should you be subject to punishment? Beyond the "should it be a crime" question, as someone who loves your kids how do you feel about exposing them to disease and suffering as adults? Imagine it this way. If you were giving them a poison which killed them in a few months would you be OK with that? If the damage hits in a few decades are you off the hook?
Recent studies from Sweden and China that followed large number of children for many years and recorded their BMI as they grew up found that their risk for developing liver disease and/or diabetes was up to 4 times greater for the obese kids.
As a parent, ponder that for just a moment. No child says, "I want to grow up and be sick every day and have to give myself lots of shots and meds, and I really want to die young". You are a big influence on their lives for a time. If you would like to learn a little more about diet here is a link that might get you started