Joe Cross' "Fat Sick and Nearly Dead 2" movie has some good points about how much a supportive community can make a difference in healthy eating.
"Fat, Sick & Nearly Dead 2 - Official Trailer"
https://www.youtube.com/watch?v=YSfQbigRlJY

Blue Zones is helping communities transform themselves into healthier places by adding sidewalks, parks, healthier menu choices, walking groups, and so on.
https://www.bluezones.com/blue-zones-results-albert-lea-mn/
"When Blue Zones and Blue Zones Project began working with Albert Lea in 2009 to transform its policies, places, and people, the focus was on helping people move naturally, eat wisely, connect, and have the right outlook—all of which can lead to living longer, better. To make transformation a reality, city leaders and the Blue Zones Project identified key opportunities for impact and sought pledges from businesses and residents. ..."

Dr. Joel Fuhrman has created an online "Nutritarian" community providing some support (although it costs ~US$8 a month for the basic level). I've found it worthwhile enough to pay for over the past decade or so.
https://www.drfuhrman.com/membership

So, there are at least some people out there trying to help in various ways.

Eating better does nor have to take endless time, but it does take some time. One general idea that works for some people is to cook a lot once a week and refrigerate or freeze stuff. But that is more problematical if you eat out a lot due to office work or travel.

Like anything, the more you do it, the better you get at it. For example, just recently I realized I could microwave a bowl of frozen blueberries for 30 seconds to have a nice quick healthy treat that is also brain-boosting.
https://www.lifeextension.com/magazine/2017/11/blueberries-e...

Still, yes, it can be difficult. The more people who do this and push back against unhealthy food, the easier it gets though, as more healthy options become easier to buy everywhere and more doctors become aware of what is possible nutritionally like reversing heart disease and diabetes and reducing cancer risks from seeing patients have successes. An an analogy, this is sort of like the more people who bicycle in an area, the easier and safer bicycling gets as there is more support for bicycle paths, bike racks, and workplace bike rooms -- and also motorists are more aware of bicycles.

Eventually maybe there will be enough political support to stop so many US Americans being killed every year via tax subsidies to various unhealthy foods:
"Why a Big Mac Costs Less Than a Salad [due to government subsidies]"
https://economix.blogs.nytimes.com/2010/03/09/why-a-big-mac-...

Related:
"‘We’re losing more people to the sweets than to the streets’: Why two black pastors are suing Coca-Cola"
https://www.washingtonpost.com/news/wonk/wp/2017/07/13/were-...
"William Lamar, the senior pastor at D.C.’s historic Metropolitan African Methodist Episcopal Church, is tired of presiding over funerals for parishioners who died of heart disease, diabetes and stroke. So on Thursday, he and another prominent African American pastor filed suit against Coca-Cola and the American Beverage Association, claiming soda manufacturers knowingly deceived customers about the health risks of sugar-sweetened beverages — at enormous cost to their communities."

I've heard that Michelle Obama originally wanted to have a campaign against unhealthy food when she became First Lady -- but there was too much political pushback, and so her effort got morphed into the more innocuous "Let's Move" with a name emphasizing exercise. One remnant of her original idea was the White House organic garden which came first. Must have been one heck of a "conversation"... (Sadly...)
https://letsmove.obamawhitehouse.archives.gov/achievements
"In 2009, First Lady Michelle Obama planted the White House Kitchen Garden on the South Lawn to initiate a national conversation around the health and wellbeing of our nation. That conversation led to Let's Move!, an initiative launched in 2010 dedicated to helping kids and families lead healthier lives."

Related:
http://www.dunkthejunk.org/blog/michelle-obamas-lets-move-ca...
"However, if we judge the Lets Move campaign on its stated mission to "solve the problem of obesity within a generation" then the campaign has been a tremendous failure. This failure is no surprise to the scientists and doctors who work in the field of childhood obesity. The science based key to reversing the obesity epidemic lies in decreasing exposure to added sugars. If you tell a child to exercise more BEFORE you get them off sugary drinks then they actually gain more weight. The science is simple….A 30 minute soccer practice is NOT enough exercise to burn off the gatorade the child brings to "rehydrate" with. Every week I see children in my office who are frustrated that their efforts to exercise have failed to solve their weight problem. These children and families feel hopeless. They have followed the instructions of our national leadership and continue to gain more weight. The first thing we do is to explain the TRUTH about beating childhood obesity…. LETS NOT DRINK SUGAR. We challenge the children to battle SODATRON, the evil SODA monster, who is ravaging our communities. They must NOT drink the poison of the enemy for one month ( no sugary drinks for one month) and then they return to our office. Inevitably, upon return, their weight has plateaued or even decreased. More important then the successful weight loss is that THESE CHILDREN FEEL EMPOWERED, their sense of hopelessness has disappeared." [Emphasis in the original.]

Refined starches are also part of the issue since the body converts them quickly to sugar. Basically, people need to eat more fiber (e.g. blueberries, carrots, watermelon, lettuce, cucumbers, squash, beans, whole-as-in-visible grains, sunflower seeds, walnuts, mushrooms, etc.) and avoid overly-concentrated high-caloric foods while escaping "The Pleasure Trap":
https://web.archive.org/web/20150430050047/http://drfuhrman....

But politically, the message to stop drinking sugar water etc (let alone stop subsidizing such industries with tax dollars) was something Michelle Obama could not directly say politically even if apparently she wanted to from what I hear. One can argue after-the-fact about whether she (and her husband) did the most that was possible at the time given many other priorities. Hopefully the political situation will continue to improve in any case -- perhaps including from legal actions like the one mentioned above.

An interesting search for anyone who wants to go down the rabbit hole: "sugar vs cigarettes".

And another search to link it back to the original topic: "sugar and depression".