1. It's all about supply and demand. You have to increase the supply so price drops. Stop agricultural conservation and allow farmers to grow good crops on that land. Stop farm raising seafood. Do a google search for what those fish are fed.
We do not have a supply problem. Supermarkets toss billions of dollars in fresh produce per year.
Not to mention the billions wasted because Americans want to eat pretty fruits and vegetables. Increasing supply will not lower the costs at all. Government can lower the costs by placing incentives on healthy eating - Subsiding healthy foods further and taxing unhealthy foods. Even then, you have to change unhealthy habits before people jump into buy
Now to be fair you'll never see 100% healthy population but these industries will be less than 25% of what they are today if the focus was on preventing being sick, not what to do after being sick.
There are actually some studies about the impacts on economic growth from the health of the population.
Sure some industries would not do as well, but overall it would be better for economic growth if we were healthier.