My opinion of fast food is on two fronts, one people are in different socioeconomic situations and find it borderline cheaper to eat that rather than making a home cooked meal which requires getting groceries, having everything for a meal, then actually making the meal. I'm sure plenty of low income parents resort to fast food because of it's convince and limited time. Not all parents work a regular 8 to 5 and can be home early enough to make a proper meal. Especially when its a one parent household. Gets difficult to make enough money then making time for proper meals while having 2 or more kids. Requires some critical thinking as well and absolutely relates to overweight/obese children. The other front is people are just on the go and resort to a quick bite of something that they can be in and out. Generally I see it as a once a week or less kind of thing for the other part.
My opinion is Fast food is gross. I used to eat that stuff about 3 times a week, then i completely changed my diet to better eating habits. If i ever eat anything too greasy i immediately get stomach pains and contemplate making myself throw up to feel better. No more sugary drinks, no more beef products, limited alcohol maybe twice a month at most, no more fast food, i do run for donuts once or twice a week though.