No wonder 21 percent of Americans say contradictory health information is their biggest obstacle to eating right. That health is an inexact science, for starters. That research moves slowly and not always forward. And that you can't always believe everything you read. No one is willing to wait and see how it fits in with what else we know.
Scientific knowledge is built one piece at a time, the result of many studies over long periods.
Experts analyze the findings, throw out odd ones and accept those that point to the same results time and again. All studies are not created equal. My best advice is to look at everything with some skepticism. Different methods result in different findings. If a group of people is observed, for example, scientists can only spot trends and make educated guesses about why they're happening.