When Crosby, Stills, Nash, & Young sang "Teach Your Children Well" in 1969, they were imploring parents to raise children with "a code to live by."

More than 50 years later, we still need to be reminded of how important that is — especially when it comes to kids' nutritional code of conduct.

Two new studies reveal that the food choices kids make (and that parents make for them) can lead to serious health problems as adults.

The first, published in JAMA Cardiology, found that adolescents ages 12 to 18 with elevated “bad” LDL cholesterol and triglyceride levels are headed for coronary artery calcification in their 30s and 40s. That means they're at risk for premature stroke, heart attack, and dementia.

The second study, conducted in a lab, indicates that eating too much fat and sugar as a child can cause a lifelong disruption in your gut biome, affecting everything from glucose regulation to immune strength.

And the researchers say it's not easy to repair a biome once the damage is done. You may need to take probiotics long-term. Stop taking them and the microbes you're beneficially introducing into your gut often fade away.

Bottom line: Feed your kids whole, high-fiber, largely unprocessed foods, with no added sugars or syrups, only 100% whole grains, and lean proteins (maximum one serving of red meat a week, and no processed red meats).

Then they'll have a fighting chance to avoid America's epidemic of diabetes and obesity.