Those approaches, for unhealthy eating in particular, can be a real challenge, because they bang hard against the reactor core of our economic system -- consumption. Consumption and lots of it. Like tobacco, the fight for healthy eating will challenge the heart of what companies do: sell as much as they can.
It's easier, more effective, and cheaper to let healthy bodies fight off disease and infections than to weaken those defence mechanisms and then compensate for them medically. If we want a stable health system, we must put more resources into reducing pollution and environmental degradation and creating a way of life that keeps bodies and minds happy and in good health.