The best thing you can do to teach your child how to take care of themselves is to get them into the routine at a young age. Cook them healthy tasty food and teach them to do it too when they reach an age where you can realistically start doing that and do lots of outdoors activities with them like going for walks and bicycle riding. Most of the time people who do nothing but sit on their ass and watch television or play video games while eating junk do that because that's what they grew up with. Their neglectful parents plopped them in front of a screen and lazily tossed junk food their way. If they grow up living a healthy lifestyle they're likely to keep doing it themselves as they become independent, and pass those habits onto their children as well.