Statement from Facebook saying : “In our ongoing efforts to improve the quality of information in News Feed, we consider ranking changes based on how they affect people, publishers and our community as a whole.
We know that people don’t like posts that are sensational or spammy, and misleading health content is particularly bad for our community.
So, last month we made two ranking updates to reduce (1) posts with exaggerated or sensational health claims and (2) posts attempting to sell products or services based on health-related claims.
For the first update, we consider if a post about health exaggerates or misleads — for example, making a sensational claim about a miracle cure.
For the second update, we consider if a post promotes a product or service based on a health-related claim — for example, promoting a medication or pill claiming to help you lose weight.
We handled this in a similar way to how we’ve previously reduced low-quality content like clickbait: by identifying phrases that were commonly used in these posts to predict which posts might include sensational health claims or promotion of products with health-related claims, and then showing these lower in News Feed.
We’ll continue working to minimize low-quality health content on Facebook. “