Anything that spikes blood sugar is going to cause problems because the individual is stuck riding a sugar high and attempting to prevent or get out of the following crash. This is a daily, hour to hour struggle. Describing it as anything less would be a disservice. Trying to not eat after a blood sugar crash is as difficult as a male with peak testosterone passing up sex.
Dropping soft drinks, if you substitute with water/tea/coffee, will be a life altering change. I did it, dropped 10 pounds within a month, never gained it back, (already fairly thin at that point) and stopped getting cavities. Over the following years it made it so much easier to convert my diet from pizza/frozen foods to fresh vegetables and unprocessed meat. I drink minimal alcohol, but for those individuals who drink heavily giving up soft drinks may not prove to have much or any impact.
There are food products that should be consumed rarely -- holidays, and humans are consuming them every day. The behavior goes from every day to perhaps 50% of the food consumed is stuff that any registered dietician will say isn't very healthy for you. Just sit in a grocery store and watch what morbidly obese people purchase verse someone who is thin and fit (and not a drug addict.) Night and day.
The science has come a really long way since I was a child in only the 1990s. We believed the only healthy diets were extremely low fat. Get rid of fat whenever possible, exercise, and you will be very healthy. No on credible believes that anymore. The problem now is largely behavior modification methods. Perhaps a success with behavior modification will trigger challenges pivoting the US food supply off corn/soy/wheat production but that is solvable.