> Very typical example is the corn lobby group, whose result on the market is to cause junk food to be much cheaper than nutritious food
Junk food is cheap because it is engineered to be cheap (particularly, to have a long shelf-life to avoid losses which drive up the price of what actually does get sold to the customer to subsidize the costs of what doesn't do to losses.) The effect of the corn lobby and the resulting subsidization isn't to make junk food cheaper than nutritious food so much as to encourage the use of corn products in junk food by making corn products cheap compared to other alternatives to corn products for making junk food.
Junk food is cheap because it is engineered to be cheap (particularly, to have a long shelf-life to avoid losses which drive up the price of what actually does get sold to the customer to subsidize the costs of what doesn't do to losses.) The effect of the corn lobby and the resulting subsidization isn't to make junk food cheaper than nutritious food so much as to encourage the use of corn products in junk food by making corn products cheap compared to other alternatives to corn products for making junk food.