Lots of people who are obese have tried like hell to "get in shape" and failed. It's not actually a slam dunk solved problem to say "Just lose the weight."
It pretty much is a slam dunk solved problem to say "If you are deficient in X, redress that." We know how to redress a vitamin D deficiency pretty confidently, simply and in a straight forward fashion.
I lost several dress sizes without trying by redressing other things, primarily nutrient deficiencies. I focused on eating an aggressively nutritious diet to redress a long list of deficiencies rooted in a genetic disorder that causes gut dysfunction.
So my experience fits with the general idea that "Solving obesity is harder than it looks and the solution may be something non obvious in any given case." Maybe our mental models of what is going on there will evolve and what I am saying will be "the obvious answer" to future generations, but it's not what is currently believed to be what works to solve obesity.
The current mantra is "Calories in. Calories out." and leads to metrics like "Eat less and exercise more" and some people find that wholly unworkable or unsustainable for various reasons.
Sorry, didn't mean to imply it's easy to lose weight, although I see that I did. Just meant that things to be encouraged (to reduce ones covid risk) don't necessarily need to be drugs that are proven to treat the disease.
Including taking your vitamins, even if you don't normally.
Yes, I agree, people should be doing the "easy, obvious, low risk" stuff first (if they can -- lots of people don't have the money, can't exercise adequately because of lock down, etc).
One of the problems is that is an inherently hard sell. People are terrible at measuring the disasters that should have happened but didn't.
If you convinced everyone to take their Vitamin D supplements, you would have an extremely hard time measuring the deaths that didn't happen but should have and an even harder time convincing the general public you weren't making up BS as click bait.
This is the bane of my existence. I have a serious medical condition and I know what the path not taken is supposed to look like and I've been getting better for nearly two decades when the condition is supposed to involve a steady and irreversible decline and I get told all the time that I am full of baloney and I can't possibly know that what I'm doing is effective and "X number of years of steady forward progress is just a wild coincidence -- stranger things have happened" and on and on.
Even people who believed me and took my advice have told me "I gave x, y and z nutritional things to my child and they are in the ER less but they aren't on less medication." by which this person meant the child's maintenance drugs were the same. But they implicitly failed to count the fewer antibiotics, steroids and other emergency treatment drugs as "less medication."
If you normally are in the ER every couple of months and need antibiotics for a month afterwards, being in the ER less constitutes a very significant reduction in use of medication. So this person was seeing results and going "But my child still needs just as much maintenance drugs, so the drug use is the same as before" when it absolutely wasn't the same as before.
So what you will see here is that the general public is much happier if you can tell them "X number of people were saved by a vaccine/antibiotic/ventilator/hospitalization" than if you tell them "We convinced the entire nation to take its vitamins and saw a dramatic reduction in incidence of disease."
If you tell them the second thing, the entire world will rise up and go "You are so full of shit. That's just a coincidence man. We didn't even need to take our vitamins. It just fucking died out for no apparent reason and you made me waste all this money on vitamins, you shit head, you."
So I've mostly quit trying to talk about "Things you -- yes, you as an individual -- can do to try to cope with this global pandemic." because I'm tired of being attacked with bullshit accusations of "practicing medicine without a license" and other crapola of that ilk.
I'm pretty damn sure I will survive this -- unless I stupidly try to be helpful, in which case an angry mob may decide I am somehow to blame for something. So: Whatever. "You fools do whatever the fuck makes sense to you and leave me the hell alone."
Low-hanging, non-risky fruit first.