This is a complex issue, and it's heartening to know some health experts are trying to resolve it. However there are several things proposed that won't necessarily change things at all, and I'm speaking from the perspective of this issue in the US. Other countries will have different circumstances.

What won't work:
1) Taxes
2) Wage control
3) Banning products, commodities

What could work:
1) Sound nutritional science embraced by the government, medical communities, and acknowledged by food producers, manufacturers.
2) Freedom of choice based on awareness of #1.
3) Social pressure and pressure at the cash register on food producers, manufacturers, and medical communities to provide products and services supporting the new Dietary Guidelines for Americans (DGA) that will lend credibility to the new science with supporting guidelines.

In a free-market society, purchase decisions are made by product quality, cost, and availability. Freedom of choice allows consumers to purchase what they need based on their preferences, awareness of product quality (to include whether it's actually good for health), and affordability. Note that affordability is usually last when one is addicted to a product like tobacco, as the addiction overrides a normal elasticity of demand curve in these cases. In other words, addicts tend to ignore cost when purchasing these substances. This applies to processed carbs as well, as I can state with conviction that i'm a recovered carb addict, and price never would stop me back in the day.

So, we can propose taxes and penalties, but what really caused the massive rejection of tobacco in the US was the fear of death from cancer. The medical community overwhelmingly communicated the message that tobacco use was fatal, and it worked. The same can be said for carb consumption following the Standard American Diet and following the previous versions of the DGA. Unfortunately, there is much disagreement among the nutritional science, medical, and pharmaceutical communities with food, as they each have vested interests that are in conflict with the ability to form and distribute a unified, powerful message to the public. It's this confusing message that enables people to rationalize that every type of food is safe in moderation. In other words, there is no common message embraced by the very authorities the public tends to find credible.

It's interesting to note that when the Food Pyramid was released in 1978, Americans adapted and followed it faithfully. When it became MyPlate, same thing. Americans listen and adapt their food consumption choices to whatever is recommended by the authorities. Americans are compliant when it comes to health, to their detriment considering the dietary recommendations since 1978. It's appalling that we're in this situation, but I'm convinced that the "authorities" will not readily change due to massive conflicts of interests. It must happen with an ever increasing knowledge base of healthy eating touted by new authorities who can speak of new scientific findings supporting a change in a healthy way of eating. It's happening today, but very slowly, as there are many touting different ways of eating based on mythical science and hidden and not so hidden agendas. Yes, it's a mess, but if people pay close attention, they'll see the fog is lifting slowly with more authorities starting to transition to sound science and healthy eating experiences proving the ability to recover health through lifestyle changes.