I see a lot of people with stress and despair related problems such as high blood pressure, heart disease, obesity, alcoholism, drug use. Diet can be an issue as well but diet problems on these come from stress management tactics, it's not the diet that's the root cause here.
Currently a major source of stress is the general political atmosphere of endemic bullshit, violence, fake news, lies, shout downs, cancel culture, cover ups, self dealing, and all this on both sides. And if you say both sides both sides jump down your throat trying to bullying you into agreeing with them their side whatever it is is perfect and the other side are literal demons who need to exterminated. By not agreeing only one side is at fault, then you as well are labeled a demon worthy of extirpation as well. Choose sides or be cast into hell. But choosing either side is to buy into a delusion.
Another cause of poor health has been mentioned: the health care system really is shit for most people. My insurance runs over $20,000 a year for a really crappy policy that doesn't cover anything since everyone is out of network or there's a copay that is more than the cash price, meaning I just pretend I don't have insurance to save money. Any hospital emergency I can be assured that either the plan doesn't cover the hospital at all or doesn't cover the people working there. In network coverage for anything involving more than one person doesn't exist. And although many doctors are good people and competent a lot more are money grubbing and incompetent, having practices managed or advised by MBAs with maximum profit as the sole motive. Specialists are particularly hard to get ahold of and charge absurd amounts compared to literally every other country in the world.
How to fix any of these? None of it is ever going to get fixed. The deep state is not just a government thing, it also extends to medicine, teaching, police, and other professions which have invisible networks that will thwart any attempt at reform or improvement to protect their own positions and lifestyles. Trying to fix it is a waste of time that only leads to being made a target of attacks, and introducing massive stress into your life. One might as well try to fix communism from inside Stalin's Soviet Union. You'll only be disappeared or end up dead. Best instead to figure out ways to have as little to do with the system as possible, and undermine it whenever you have the opportunity, hoping it will eventually collapse. The only way out is collapse at this point. Some cars are so far gone they can't be fixed. Likewise with houses. I've seen people try to restore an old farmhouse or victorian with a rotted foundation and floors and spend hundreds of thousands of dollars ending up with a crappy house with poor energy efficiency and little resale value. They are broke and stressed out and just spent a decade exposing themselves to black mold and sometimes things like asbestos. They could instead have demolished it and built a full size replica using modern efficient methods for a tiny fraction of what they spent "fixing" it. Why did they pursue restoration instead? Because they bought the rotted house for what they thought was a bargain and ignored its long term costs, and also they "fell in love" with it through simple familiarity and comfort of knowing it was theirs. Tearing something down or throwing it out and starting over again is the only way out of things that are far too rotted and broken to be worth fixing. Political and economic systems, houses, cars, and relationships all fall under this rule.