You are right that I should not have singled out fast food. Included would be grain based desserts, soda, alcohol and maybe others. Grain based desserts and soda together make up 12% of caloric intake alone[0] and serve almost no nutritional value while providing little satiety.
Another point, while I did say that "The entire point of those ads to get people to eat fast food" what I really meant is that they make people want to eat in general[note 1]. What this means is that fast food ads can be harmful even if they do not cause the viewer to buy fast food. What this does is contribute to a culture of consumption which is part of what I meant when I said "The only way to solve this problem for the whole population [...] is to change society and how it views unhealthy food." I did not mention sit down restaurants because they generaly do not advertise. My suggestion was "off the top of my head" and not fully thought out. I'm glad you made your comment because I did not express my reasoning clearly.
[0]https://epi.grants.cancer.gov/diet/foodsources/top-food-sour... page 77
[note 1] That is, the "point" of the fast food ads collectivly are to generate a demand for fast food from the point of view of the advertisers, but the effect, while more pronounced for fast food, generates a general demand for caloric intake.