To be honest, not all fast foods are Junk food, most are super healthy as much as they are fast, and sometimes very delicious plus their affordable rates(so do people think). A world without Cafes and Restaurants producing fast food would probably go hungry and weak if you must agree with me, somehow; people living in free world are lucky to have this options available to them, because in some places hunger kills faster than wind.
So the question really is; would you bother on how to manage your graceful bodies as human over having a belly filled with food and energy? Remember, a belly filled is a body put to work right?
Regardless of the Several studies and research works that has shown that fast food aka Junk foods are not too good for our health, it's still part of our lives across the globe and it's rather unfortunate that this is just what most people can afford. Healthy foods can be expensive for someone living below the poverty line. Although the body pays the price as time goes on, the arteries, heart, liver and kidney all suffers later on because of the high salts and other elements present in these foods, unlike homemade food.
Food made by an individual at home have good proportion of ingredients used, you measure whatever you are putting in your body adequately. It is essential that when it comes to the human body and maintaining it, no doubt it is important to take things seriously and never overdo things or not doing it adequately I.e not eat too much carb or fats or salts or refined sugar which are common in fast foods world wide.
But we can't go without feeding, which is why fast foods can't be ruled out completely. For example, a subject with a very healthy lifestyle (i.e eating balance diets and exercising appropriately) could get away with occasional junk intake but it would be based on a good ratio between healthy living and less healthy lifestyle to get away with this, provided that its not done regularly.