I think we have been answering and discussing two different aspects, or two related questions.
Question 1 is: Is it - IF the skill and time and opportunity (working kitchen) to COOK is availaible - cheaper to buy veggies and (whole-grain) pasta to eat healthy (by cooking yourself a nutritous meal)?
The answer is YES in most cases BUT varying wildly depending on where you live. Obviously, oranges will be much more expensive near the arctic circle than in California, compared to staple foods. Not all neighborhoods have supermarkets with cheap and fresh veggies (wilted veggies aren’t very useful anymore). Not all shops mark down stuff, or have specials. And so on.
Question 2 is: IF cooking isn’t possible - for some of the reasons already given (lack of skill, of time, no working kitchen) - is fast food and junk food cheaper?
The answer is YES - cheaper than the alternatives, again depending on location. If you work in uptown city in a good office, you might have a mess that serves food to the employees. You might have sandwich stores which offer salad for lunch. But in most cases, McD will be cheaper than a restaurant (esp. if people use coupons and special offers), and a frozen dinner is cheaper or equal to that.
Question 3 (the three strenghts of the Spanish inquisition are …) is: WHY do more (nobdoy sensible says “all” = 100%; but statistics show more than in other income groups) poor people (as defined by income class, not by ethnicity; but low income overlaps certain ethnic groups, not 100% - there are always exceptions, but to a major percentage) eat junk food and fast food (and therefore become overweight)?
The answer to that are (as have already been explained)
-lack of skill, time and opportunity to cook themselves (which is not equal to being lazy)
- lack of education about the importance of healthy nutritioun, and why fast food is bad in the long run (which is not equal to being wilfully ignorant)
Now, personal anecdotes of how you manage to cook yourself on a tight budget are nice and interesting to answer Question 1. But they have no impact on question 2 and 3, esp. 3, because when talking about large groups of people (again, not a 100% - there are groups with low income who can cook healthy and do so, for various reasons: traditional ethnic cuisine, knowledge about healthy eating, simply likes cooking…; but statistics and research shows that the causes lissener and others gave apply to many people) - personal anecdotes DON’T invalidate the reasons and causes.
It’s like asking “I don’t smoke, why does everybody else? They must be lazy to not stop” - because not 100% of other people smoke; some people have managed to quit; but the group of people that still smokes has several reasons for doing so. All my personal anecdotes don’t negate these reasons for some other people.
In a way, it’s ironic that I’ve come across as defending junk food and fast food; because the arguments given for cooking healthy yourself are the same arguments I myself use when trying to convince people to switch from the traditional meat diet to a veggie-oriented, healthy, organic style, and the argument is “Well, I can’t afford organic”, I counter with “cooking is healthier then ready-made food; buy special offers; buy smaller portions, things taste better, so you need less”. However, these are personal discussions, and often I can’t persuade people, because cooking is too much of a bother/ not enough time for a single mother to shop for specials and cook.
Besides, although I know about healthy food, and buy organic, I don’t cook myself, so I can understand when people don’t like to, even if it would be better.