[joshspankit]

I missed where the example was diet, but even there:

Old science said “we observe that people who eat excess fat die younger, therefore we conclude that fat is bad”

Later, science said “Now that we understand more about the body, we now know that we need a certain amount of fat to live because among other things our brains are made of fat and we efficiently use fat as fuel. We have also found that there are different types of fat and that some people process each type differently. In addition, the previous conclusion was too broad. Those people who died younger also had inactive lifestyles and ate mainly processed food that’s full of sugar so we threw out most of that old data and started over with a better method. We have now observed that people who consume only healthy fats live longer than people who don’t. Therefore we conclude that a certain amount of healthy fat is good for you.”