One of the excuses that are offered for not eating healthy is not being able to afford it; in fact this is an interesting question, how much does it cost to eat healthy; and one that is attempted to be answered in this discussion.
Going by the fact that the average daily consumption is 2000 calories, how much do 2000 calories cost? If you have healthy items such as Greek yoghurt with organic raspberries for breakfast, and then turkey avocado wrap, and later wild caught Alaskan king salmon, green beans and whole wheat bread for dinner, some strawberries and cream, then this will set you back a pretty penny. Here 2000 calories will cost you about 26 dollars. On the other hand, you can also buy 2000 calories for about 5 dollars if you choose to get those calories from junk food such as donuts.
Clearly it costs more to eat more nutrient dense food such as fresh fruit, veggies, lean meat, fish and other seafood. On the other hand beans, starches and grain are cheaper. Perishability is one of the main reasons for this; but there is also the contribution of government subsidies that send up the cost of healthy eating.