It means you should never do what the mass media recommends you do based on some biological or medical study. The data are usually complex and can be analyzed in different ways, while the nincompoop science writers at major media outlets like the New York Times Science Digest report it badly, with bias but without nuance. A lot of times they miss the point or exaggerate the findings because they don't know anything about methodology and statistical analysis.
It means that you shouldn't take most of this stuff seriously unless you read Lancet, JAMA, Nature, Science, Brain, or more obscure scientific/medical journals and have the expertise to figure out what you're really reading. And it means you should use common sense. Eat a balanced diet, don't smoke (or just smoke pipes or the occasional cigar), don't do illegal drugs, take a multivitamin, have a glass of wine with dinner every night, exercise, relax, sleep, have fun, keep tabs on your blood pressure, take prescribed meds, get and stay married, don't take part in Ironman competitions, pray, keep pets, etc. etc. etc.
"Experts" are under tremendous pressure to publish and get their names out there. Otherwise they stuck actually having to practice medicine.
I so agree with your tagline! I never do what the mass media recommends; just my obstinate nature I guess. I just hate getting into spats with my family doc, when I argue against the 'latest' expert opinions on things. Expert, of course, is defined as: ex= has been, pert(spurt)=drip under pressure.