Eating healthy is pretty simple: A plant based whole foods diet will do it. The 4 major food groups are as follows: Beans, Grains, Fruits and Veggies with maybe a little bit of nuts, and meat maybe once a week.
For real though- the big battle is convincing people of this simple but boring fact. Limiting portion size and adding a little moderate exercise is all you need but it doesn't sell books and make the social media rounds. What is the best way to portray this to the public?
Make your own fast food restaurant chain. Sell healthy full-feeling food in correctly sized portions for competitive prices. Include meats for people who mock people who eat "rabbit food". Include vegetables for people who hate meat. Good luck keeping your menu current.