This quote is the part you should take away with you, I think. It's great advice. The rest of the article consists of largely the standard anecdotes on how long it takes the scientific community to really do a decent job of evaluating complex proposals in complex systems, and how that timing interacts poorly with the entirely admirable urge to get something done by deploying applications of scientific findings that might do some good in the world:

"So how should we respond the next time we’re asked to believe that an association implies a cause and effect, that some medication or some facet of our diet or lifestyle is either killing us or making us healthier? We can fall back on several guiding principles, these skeptical epidemiologists say. One is to assume that the first report of an association is incorrect or meaningless, no matter how big that association might be. After all, it’s the first claim in any scientific endeavor that is most likely to be wrong. Only after that report is made public will the authors have the opportunity to be informed by their peers of all the many ways that they might have simply misinterpreted what they saw. The regrettable reality, of course, is that it’s this first report that is most newsworthy. So be skeptical.

"If the association appears consistently in study after study, population after population, but is small — in the range of tens of percent — then doubt it. For the individual, such small associations, even if real, will have only minor effects or no effect on overall health or risk of disease. They can have enormous public-health implications, but they’re also small enough to be treated with suspicion until a clinical trial demonstrates their validity."

------------------

From something I wrote a while back:

"The scientific method is the greatest of inventions: when used to organize and analyze the flawed output of we flawed humans, it leads to truth and discovery. It is how we sift the gems of progress from the rubble of short-sighted human nature, magical thinking, willful ignorance, and other self-sabotaging but entirely natural behaviors.

"The scientific community doesn't produce an output of nice, neat tablets of truth, pronouncements come down from the mountain, however. It produces theories that are then backed by varying weights of evidence: a theory with a lot of support stands until deposed by new results. But it's not that neat in practice either. The array of theories presently in the making is a vastly complex and shifting edifice of debate, contradictory research results, and opinion. You might compare the output of the scientific community in this sense with the output of a financial market: a staggeringly varied torrent of data that is confusing and overwhelming to the layperson, but which - when considered in aggregate - more clearly shows the way to someone who has learned to read the ticker tape.

"So how do you read the output of the research community for a particular topic of interest? Firstly you have to recognize that the output of any single researcher is meaningless when considered in isolation. At least a good half of the results produced by scientists are in some way flawed. That is par for the course when working at the cutting edge of new knowledge, and no slur upon the hard work of those involved - they know the odds. The high failure rate of risky ventures like scientific research is why we need the scientific method to weed out those failed results as time progresses and new results emerge. So when you read up on a topic of current research, you need to read around the subject: dig in to various sources, find the work of multiple scientific groups, and assess the support for different theories and interpretations."

------------------

In terms of evidence for greater health nothing comes close to the twin mountains of data in support of calorie restriction and regular moderate exercise. If you are doing other things in the hopes of health without covering those two line items, then you really have to accept that you're not taking the best, most proven path.

Well, actually that's a complete lie. There is one thing that exceeds both of those items, and that is progress in medical science towards better treatments. The faster that goes the better off you are - so you should also put in time and energy to helping that happen. As you get older the calorie restriction and exercise fade as determinants of health in comparison to the present state of medical technology, and thus it becomes ever more important that you helped back in the day, giving your contribution a chance to snowball in effect.