Richard Hanania in his newsletter:
Progress in the worlds of nutrition and everyday health has stalled, as has medicine to a more limited degree. We know a few things. You should exercise, avoid smoking, not be fat, and not jump off tall buildings. Besides that, there isn’t much we can tell you with certainty about what to eat and how to live your life.
In science, you begin by picking the low hanging fruit. Smoking increases your risk of lung cancer somewhere between 15 to 30 times. With an effect size that big, one doesn’t really need a scientific literature to know what’s going on. A single doctor who sees tens of thousands of patients over several decades would probably be able to come to understand the harms of smoking on his own.
But what about smaller effect sizes?
More here.