That brings me to the most important question: just who do you think you are to tell people what to eat?! Yes, as a doctor you can advise them on better diet. And yes, agricultural subsidies are a disgrace. However it is not a legitimate government function to mess with food pricing. You can advise people on diet all you want, but you should not have any power beyong your power of persuasion.
It is extremely arrogant of you to think that you know what's best for other people (who you don't even know!). And it is precisely this arrogance that's at the bottom of socialism. E.g. how do you even know that people want be healthier at any cost (in terms of diet and habits)?! To begin with, what we consider medical knowledge, changes all the time and there are plenty of uncertainties (I speak from inside knowledge - e.g. I participated in developing a mathematical model of obesity and read lots of recent research). But even if we accept the current conventional wisdom on nutrition as the last word of science, it is all statistical, not deterministic. I.e. if you smoke and eat certain diet, you merely have a greater risk rather than a certainty of certain diseases (if you don't believe that people with very unhealthy lifestyles can be very healthy for 90 years, just look at Churchill). So if you tell me to change my lifestyle, you are not preventing a heart attack - you are merely lowering its chances. Furthermore, regardless of those risks, I may well die of totally different reasons (accidents or diseases unrelated to those lifestyle risks - like lots of cancers). So if you tell me that lifestyle changes would increase my life expectancy by one year, you are really talking about percentages - not an actual guaranteed additional year of my life. But OK, for the sake of argument let's assume that you can actually give me an ironclad guarantee that if I do certain things (and stop doing other things), I will live a year longer. Now, I am supposed to deprive myself of some important pleasures for my entire life, and as a reward my life will be extended from 82 to 83 years and I'll get another year at an age when I'll be in steep decline physically and mentally and will not even be able to enjoy life very much (so I'll almost certainly be a loser in terms of QALYs). Just why exactly do you think I should be happy to take that deal?! And who or what gives you the right to nudge me (with taxes etc.) to take such a deal?! Is it because you think I am stupid and got brainwashed by deceitful marketing while you are so smart that you are not only totally resistant to all marketing but also know what's best for me better than I know myself?!