Listen to the interview with Dr. Marion Nestle of New York University on Food Politics: How the Food Industry Influences Nutrition and Health.
The narrative that drives the food industry philosophy, like pretty much every other philosophy of contemporary capitalism, is one of personal choice and responsibility. It should be - but isn't - unnecessary to point out that the insistence on personal choice intentionally ignores the fact that there are such things as systems of law, distribution, education, economics, et cetera, et cetera, et cetera, and that those systems are constructed in ways which discriminate against certain groups of people. More than that, the dismissal of the influence of factors external to one's individual choice is a particularly subtle and insidious form of victim-blaming. To emphasize personal responsibility assumes that all possible choices are equally available to everyone, and all one has to do is decide which one to pursue. Implicit in that is the assertion that if you are in a difficult situation, whatever it may be - overweight, un- or under-employed, homeless - you are there specifically because of choices you have made autonomously, and therefore have no one to blame but yourself. This is the set-up required to talk about welfare and health care as "handouts", and it is how the food industry - again, like so many others - shifts the focus from their activities to their consumers'. From this springs the notion that, say, people on the dependents' benefit are "breeding for a business" (or, for that matter, the idea of the "frivolous lawsuit" or the "honeytrap" - both false ideas spread about who files lawsuits or rape allegations and why, both designed to undermine and silence the people casting the allegations, often already-marginalized groups like the elderly and women). Or, to bring it back to food, the demographics of people who are overweight.
Central to the success of the food industry narrative is the idea that there is no such thing as good food or bad good, it's all just food, and it is only about the choices you make about which foods to eat. I don't think it's controversial to assert that there are, in fact, good and bad food - or at least better food and worse food - and that limiting the worse food (fats and sugars) and eating lots of the better foods (fresh fruits and veg) is the key to a healthy diet. But the good foods we should be eating lots of tend to be the unprofitable ones, at least in the modern supermarket aisle: fresh, whole foods, by their very nature, have no added value, and added value is how profit is made. Processing foods adds value (potatoes cheap, chips expensive), and allows the companies to sell product for higher prices and contribute more of the share of that price to their advertising departments. This is particularly true with commodities like corn or soy, which are so heavily subsidized as to be almost free, and which, as a direct result of those subsidies, are massively, unfathomably abundant. They become the food equivalent of stem cells; they can be made into pretty much anything, and they can be sold for cheap cheap cheap and still make an enormous profit.
Also, the further from its original state a food gets, the less nutritious it becomes, and that includes preserving and even cooking. I'm not suggesting we all start raw diets tomorrow - I could not live without cake or red curry - but have you ever thought about why processed food stays edible for longer? Processing or preserving food makes it keep longer because it is less nutritious to the organisms that eat it and make it go bad. That's why McDonald's fries or Twinkies will keep forever: they hold no nutritional appeal to mould or bacteria, which simply don't recognize them as food. They are literally not food. From here on in, I will therefore refer to them, as Michael Pollan suggests, as edible food-like substances.
There is a direct relationship between weight and wealth, and that has always been true for very obvious reasons (aside: check out the differences in results when you google "weight and wealth" versus "poverty and obesity"). In times when food is scarce, which has been the vast majority of human history, being fat is a sign of wealth and success. However, in our contemporary abundance, that relationship reverses, so that thinness becomes the domain of the wealthy, and poverty becomes the single most reliable correlative of poverty. There's a great deal of research backing this up, and it reveals quite a complicated relationship between weight and income: one 2005 study compares the rates of obesity to income disparity over 21 developed countries and finds that the greater the social inequality, the higher the obesity rates, leading the authors to conclude that the relationship is due to the "psychosocial impact of living in a more hierarchical society". But there are problems of correlation versus causation, so let's flesh out the conclusion with some of the other contributing factors, namely, the beauty bias which stigmatizes people who are overweight. For example, as Deborah Rhodes outlines in her book the Beauty Bias, people who are overweight are less likely to have a lot of friends or be respected in their peer group; they are less likely to marry and have children; they get lower grades; they are less likely to land a job and they will be paid less for the jobs they get. They are also, obviously, more likely to suffer from health problems, which also impacts job performance, and they are less likely to seek medical attention for these problems. These factors, in conjunction with food industry marketing initiatives which specifically aim to sell the highest-calorie, lowest-nutrition edible food-like substances specifically to low-income families, conflate to perpetuate and extend a deeply unequal, strictly hierarchical society, which keeps poor people fat, and fat people poor.