This seems impressive and strong confirmation of Dave’s interpretation, until you take into account the point that Parker Pope makes in her article about this very database, which is that the NWCR is nothing more than a compilation of anecdotal accounts. Parker Pope quotes an obesity researcher from Yale (who happens to be obese himself, apparently intractably so) noting correctly that “while the 10,000 people tracked in the registry are a useful resource, they also represent a tiny percentage of the tens of millions of people who have tried unsuccessfully to lose weight. All it means is that there are rare individuals who do manage to keep it off.” And that is indeed all it means. It says nothing about how large or small a percentage of obese individuals can do this. It could be one in ten thousand or less. It could be one in two. We have no idea.

Of Dave’s three other references, one is a review article of behavioral weight loss programs in children that makes only the tepid claim that “limited evidence suggests” adolescents can maintain a weight loss of 4 to 8 pounds for a year. One is a study in adults claiming that two thirds of those who got intensive behavioral modification did indeed maintain at least a 20-pound weight loss for one year, but it then says “three- to 5-year follow-up studies showed a gradual return to baseline weight.”

The last reference reports that subjects who averaged a 65-pound weight loss over five months gained back all but 15 pounds after five years. This is a glass half full, half empty case. Dave apparently looks at the 15 pounds and says, this is reason to believe Parker Pope was wrong. Parker Pope, I suspect, and I would look at the 50 pounds regained as evidence that she was right.

Finally, Dave evokes the Look Ahead study, a massive trial predicated on the notion that maintenance of a five percent weight over ten years is clinically meaningful. Dave says he wouldn’t t be so quick “to dismiss a 5 percent loss as nothing to celebrate.” He calls it a “proof of concept, putting the lie to claims that we are genetically fixed to have a certain weight.”

Now consider as an example a woman like Parker Pope, who says in her article that she is 60 pounds overweight. Let’s assume that our subject is of average height, 5’4”, and so an ideal weight might be 140 pounds (a BMI of 24). If she’s 60 pounds overweight, she would weigh 200 pounds and have a BMI of 34, well into the obese range. Dave’s implication would then be that if our hypothetical case dropped from 200 pounds to 190 (BMI 32.6, still obese) and maintained that indefinitely, she should consider this a reason to celebrate and a refutation of the central point of Parker Pope’s article. I would argue otherwise and I suspect Parker Pope would as well.

In interpreting science and medicine for the public and investigating issues so critical to the public health, we’re all biased, just as scientists are, by our perspectives, our experiences and our preconceptions. If we don’t start off biased, we will soon find ourselves consciously or unconsciously taking sides, and that will bias our perceptions from then on. In a world in which virtually any argument can be made from the evidence at hand, our ultimate task, just as it with science itself, is to communicate reliable knowledge. Here, the legendary physicist Richard Feynman made two requirements for good science that I would argue are the requisites for good journalistic investigations as well: One is “honesty in reporting results — the results must be reported without somebody saying what they would like the results to have been.” The other is “you must not fool yourself and you are the easiest person to fool.”

Gary Taubes is co-founder of the Nutrition Science Initiative, and the author of Why We Get Fat and What to Do About It (Knopf 2010) and Good Calories, Bad Calories (Knopf 2007). He’s a contributing correspondent for the journal Science, and the only print journalist to win the Science in Society Journalism Award of the National Association of Science Writers three times.