Why are the Healthy Foods Expensive

I ask this question because in America, Of of the main issues is the amount of teens and adults are over weight. It is more in Teenager.

"Today the percentage of adolescents age 15-17 who are overweight is about 50% higher in poor as compared to non-poor families, a difference that has emerged recently," said Johns Hopkins' sociologist Richard Miech, the study's lead author.

http://www.usatoday.com/news/health/2006-05-23-obesity-teens_x.htm

So of food is so expensive, How can they eat healthy? It seems like all the Bad foods are cheap and available. According to Why are healthy foods so expensive? (http://straighthealth.com/pages/qna/healthyfoodexpensive.html It is expensive because it deals with economics. Healthy food, the capital is expensive and cheap foods are cheaper to make. It is difficult for the poor to be healthy with prices so high but it is worth it because, the country is "Starting to notice that buying expensive food now can prevent expensive hospital bills later."