People try to maintain their homeostasis for a longer life and fewer visits to the doctor. Education needs to start at a young age. A major gum in the works is the outbreak of childhood obesity. Obesity is an epidemic in many parts of the world and education is at the forefront.
A person taught good dietary habits as a child will grow with those habits and pass those on to subsequent generations.
Just telling a child you can't eat candy all the time isn't enough. An in depth talk about what candy is for and how to manage sweets is the better option.