Bringing your child up in a disciplined manner in where he will obey you is what you should do. You need to teach them in the early age before they start getting individuality and think they know everything. If it is too late, then you have to teach him on the effects of what non-satvic foods do. If your child doesn’t care about any of this then you have to tell him,”Eating food is temporary, and sins last for a long time”. If you don’t bring your child up right at a young age, you will let him have peer pressure from the other modernizing people, and your child will most likely go away from the tradition you have. Please visit the samasrayanams page, so you can have your child in the right protected path.