I thought this tweet from @WoodyOsher was pretty funny.
Everything our parents said was good is bad. Sun, milk, red meat … the least-squares method.
I wouldn’t say these things are bad, but they are now viewed more critically than they were a generation ago.
Sun exposure may be an apt example since it has alternately been seen as good or bad throughout history. The latest I’ve heard is that moderate sun exposure may lower your risk of cancer, even skin cancer, presumably because of vitamin D production. And sunlight appears to reduce your risk of multiple sclerosis since MS is more prevalent at higher latitudes. But like milk, red meat, or the least squares method, you can over do it.
More on least squares: When it works, it works really well