General trends should only be applied by trained professionals, such as physicians or dietitians, who can do so with the necessary care and attention. Unless you are a doctor, you’re right that it’s hard! In fact you shouldn’t do it at all.
It is important for people to understand this concept, because it seems to be commonly overlooked. The average person should not create a diet or fitness plan based solely on data like what is discussed in this article. Rather, it is far more healthy to defer to professionals and their recommendations in the form of interpretation of that data for guidance rather than attempting to interpret this information on your own.