You've gotten a lot of downvotes but rather than doing that I want to explain to you why your position here is flawed.
First think of every lifestyle activity whether it be food, motorcycle riding, music, etc. Now consider that there are some activities that are statistically safer than others.
If we took your position to the point of being law why would we stop at food lifestyle choices? Why not just any risky lifestyle choices? Eventually you end up with a society where individuals have less choice and freedom and are constantly obligated to live the safest possible lives.
You and I both know that isn't a desirable outcome. We should be empowering people to live the lives they choose and encouraging them to be healthy, not punishing them for make the "wrong" choice.
Consider what you just said can apply to motorcycling or buying a classic car with outdated safety features. There is no tangible health benefit to motorcycling or driving a classic car, it basically "has no positive health benefits at all" (as per your own words) and only increases risk. Show it be banned? What about every other risky hobby? If not, then neither should eating junk food which is measurably less dangerous/risky. Keep in mind that for smoking the overall trends of diminishing smoking habits in younger generations basically highlights the proof that encouraging healthy habits rather than punishing the individual is the correct way to approach this.