Your question is a heavily loaded one and unfortunately there is no quick answer.There are some really great books out there that help explain this huge issue in our country. Check out the Literature section of www.the-sage.org for some recommendations. I recommend starting with “Food Politics” by Marion Nestle!

There have been several nutritional changes in the United States that have impacted the fast food industry and society's relationship with food. In the aftermath of the Great Depression, crop subsidies took place in order to help farmers make more money for their crops while offering them at a lower cost to the public. This resulted in having an excess of these crops - namely wheat, corn, and now soy - which results in these now inexpensive products being inserted into food = processed foods. As the kitchen tool technology improved, starting with the microwave, food companies began to provide meals that were convenient to families - this made way for housewives to begin leaving the homes and start working. This convenience that once was directed to alleviate the workload of US housewives have escalated to be a source of all things unhealthy. Furthermore, these subsidies have allowed fast food companies to rise and provide inexpensive and addictive food to people, while utilizing wheat, corn, and soy byproducts. What once started out as a family treat (at a time when obesity and it's related conditions such as type 2 diabetes and heart disease were unusual and somewhat unheard of), has become the norm for many families who believe they cannot afford fresh foods. To further expound the issue, soda, burgers, fries, and bags of chips are all examples of foods whose portion sizes have increased over the decades.

It does seem that our society is moving towards a more health conscientious place. All chain and fast food restaurants are now required to post calorie counts. A lot of places now offer healthier options like fruit and salads, giving people an opportunity to make better choices when eating out. Remember, that these restaurants are not our friends, but economically driven businesses. When sales for “healthier” items decrease, so does the offering. Fast food chains are not in the business of helping reduce the obesity epidemic. In fact, their business thrives on these folks, in addition to the ones with limited nutrition related knowledge or food access. We are no where near resolution but at least there are strides being made in a direction to improve the quality of our health through smarter nutritional habits.

Like I said, just a graze of the iceberg that is our food system. I hope this information helps! Happy Eating!