Monday, February 13, 2006

Low-Fat Diets - Dogma or Data?

Main Entry: dog·ma
Function: noun
Etymology: Latin dogmat-, dogma, from Greek, from dokein to seem
1 a : something held as an established opinion; especially : a definite authoritative tenet
b : a code of such tenets
c : a point of view or tenet put forth as authoritative without adequate grounds

Main Entry: scientific method
Function: noun
1. the principles and empirical processes of discovery and demonstration that are characteristic of or necessary for scientific investigation.

The scientific method involves an observation, the formulation of a hypothesis about the observation, experimentation designed to demonstrate the truth or falseness of the hypothesis, and a conclusion that validates or modifies the hypothesis.

As I've pointed out a number of times, dogma isn't science.

Science is an objective, disciplined methodology for investigating the world around us. Scientists — those having expert knowledge of one or more of the existing scientific disciplines - use the scientific method in their efforts to extend and deepen our understanding of the world. Good scientists are open the prospect of being humbled by their findings. You see, scientific inquiry isn't about being "right," it's about finding truth through a mindset of doubting, questioning, and openness to the self-correcting spirit of scientific inquiry.

The necessary commitments of a scientist in search of the truth include:
  • A search for collectively justified knowledge (as opposed to opinions and unjustified beliefs)
  • A justification based on perceptual grounds not shaped by individual or cultural factors
  • A willingness to change if required by evidence and reasoning (open-mindedness)
  • An unwillingness to change unless required by evidence and reasoning (skepticism)
  • An awareness of the fallibility of human knowledge, and the resultant doubting and questioning

Interestingly, the words "science" and "scissors" are both related to the Greek word "schizo" meaning "to split."

Think of science as scissors: two blades of inquiry are better than one for cutting into the unknown.

Today explanations of WHI findings are being interpreted, refined and subsequently targeted to the consumer through a biased filter, with the actual data judged right or wrong depending on whether or not it supports the low-fat dogma. Discordant data on carbohydrate restriction, saturated fat intake, and metabolic syndrome, among other topics, continue to be ignored or ridiculed.

This reflects a continued mindset that is alien to the spirit of free scientific inquiry.

Just take a look at the headlines and commentary that is pervasive in the media right now:

NEWSWEEK: Dean Ornish: The Facts About Fat
The real lesson of the Women’s Health Initiative study is this: if you don't change much, you don't improve much.

TIME: The Real Story About Low Fat
What does all this mean for you? If you don't have a history of heart disease or breast or colon cancer, you can probably cut yourself a little slack on the total amount of fat you consume--as long as you avoid the bad fats (found, for example, in ice cream and ground beef) and replace them with good fats (found in olive oil, nuts and fish). We should all exercise regularly and eat more fruits, vegetables and fiber-rich whole grains. And next time someone says to you, "Hey, wasn't there a study that proved that low-fat diets aren't worth it?", you can just smile and ask that person to pass the string beans.

NEWSWEEK: The New Fight Over Fat
This study did not repeal the laws of diet as much as it refined them. It did not, repeat not, say that whole grains, fruits and vegetables can be tossed out in favor of thickly marbled beef at every meal.

CHICAGO TRIBUNE: Fat free? Not really
Even after this definitive study, though, most nutritionists (except for those in the Atkins ultra-low-carb camp) still think there's a benefit to limiting fat consumption.

NUTRAINGREDIENTS: The cost of bad research
Some experts have rightly spoken out against the studies, encouraging the public to stick with five portions of fruit and vegetables a day and stressing that people take care about fat intake...There will undoubtedly be consumers who accept these studies, people who are reluctant to change their diet or lifestyle, despite a mountain of science saying the opposite.

BUSINESS WEEK: Skip Your Veggies? Not So Fast
Based on its design, the trial had little chance of making major advances in the science of nutrition...So try to stay fit, keep your weight down, aim for a relatively healthy diet, and don't worry too much about the latest headlines in the medical journals.

US NEWS & WORLD REPORT: A low-fat diet, by itself, won't arm you against heart disease or colon cancer
Moreover, the recommended diet made no distinction between "good" unsaturated fats and "bad"saturated fats and trans fats, whose importance to heart health has been recognized since the data-gathering started. And since all the women in the study were eating fairly healthfully beforehand, it's possible that the small changes in vegetable and grain consumption by the dieting group weren't big enough that any benefits registered. Rather than focus on total fat intake, Stefanick advises, go easy on foods containing saturated fats and trans fats and eat more vegetables and fruits and whole grains.

FASHION MONITOR: Low Fat Diet Study Results Don't Prove Much, Dieticians Say
Despite findings being announced this week that a low-fat diet introduced in the middle-age years didn’t reduce the risk of breast cancer, heart disease, stroke or colon cancer, one of the researchers says people still need to focus on the types of fat they eat.

GLOBE AND MAIL: Ignore the latest study stay on a low-fat track
But just because this one study didn't find an overall protective effect, there's no reason to swap a low-fat menu for one that's high in fat.

Giving support only to beliefs within the framework of a low-fat diet undermines a fundamental element of the scientific method — the constant testing of theory against observation. Such a restriction makes objective, or even the ideal - unbiased, discussion and research impossible.

So what is the scientific community about, really? To what extent are scientific theories defined by the quest, not for truth, but for job security and lavish government funding? Let's not forget the WHI study cost almost a half-billion dollars and now researchers want more time and a stab at observing the consequence of restricting dietary fat even more, and in the meantime, the low-fat dogma will remain as the dietary approach for all Americans.

Remember it was the Director of the National Heart, Lung, and Blood Institute (NHLBI), Elizabeth G. Nabel, who said - "The results of this study do not change established recommendations on disease prevention. Women should continue to get regular mammograms and screenings for colorectal cancer, and work with their doctors to reduce their risks for heart disease including following a diet low in saturated fat, trans fat and cholesterol."

Where is the principle of scientific humility? You know that piece that is integral to science - our admission to our express lack of knowledge about everything.

What's missing in all the discourse is the reality that accumulative error certainly does apply when theories are built on theories that are built on theories that are only assumed to be true. The scientific community has a way of constructing systems of “knowledge” despite dissent at multiple points along the way. For decades there has been dissent from numerous scientists who warn that a low-fat diet is not optimal. This dissent hasn't been quieted by evidence and hard-data, but by ridicule and dismissal.

But, we laypersons rarely hear of the dissent — only the prevailing view prevails precisely because dissent and evidence is ignored. And we're seeing this now.

An empirically derived worldview is held as a matter of evidence, not faith that what you think is right is right; it’s responsive to observation of a world that’s understood to exist independently of the needs and desires that dogma so often flatters.

Empiricism therefore keeps us cognitively humble.

Implicit in the cognitive norms of empirical evidence and observation is the assumption of fallibility, the idea that we may not be getting everything quite right, that we might someday have a more accurate view of reality based on more reliable and comprehensive observations and evidence. We're seeing no sign that those committed to the low-fat dogma even consider they might have a flawed hypothesis.

This fallibilism helps to inoculate evidence-based science against the self-righteousness of being necessarily right. Those scientists committed to unfettered inquiry are unlikely to resort to threats and coercion to silence opposing views.

In contrast, we find adherents of dogmatic views of reality are unresponsive to evidence and are less inclined toward cognitive humility. Their driving assumption can be quite the opposite of fallibilism and reads like this: my revealed, intuited, empirically non-responsive worldview is necessarily true, so any contradictions of it must be discounted as illusory and wrong-headed. Since I am right, others must be wrong, and their beliefs stand as an insult to my truth.

In his famous 1974 commencement address at Caltech, Richard Feynman provided an inspiring example of how science ought to be practiced. He began by warning against self-deception, the original sin of science, saying that "The first principle is that you must not fool yourself, and you are the easiest person to fool."

To avoid self- deception scientists must bend over backwards to report data that casts doubt on their theories. Feynman applied this principle specifically to scientists who talk to the public: "I would like to add something that's not essential to the science, but something I kind of believe, which is that you should not fool the laymen when you're talking as a scientist. . . . I'm talking about a specific, extra type of integrity that is not lying, but bending over backwards to show how you're maybe wrong, [an integrity] that you ought to have when acting as a scientist. And this is our responsibility as scientists, certainly to other scientists, and I think to laymen."

That's such an incredible statement - Feynman's kind of science has the virtue of humility at its very core. Honesty and humility.

This is what has to be brought into the national obesession with dietary fat - an understanding of the obligation of science to separate personal belief & dogma from scientific investigation, to maintain that separation and be honest about it, and not to mislead the public about what has been demonstrated and what hasn't; a science that sticks to its data, that is careful to consider alternative explanations, and that does not allow itself to be ruled by a dogmatic agenda of any kind; a science that does not commit the original sin of believing what you want to believe.

A science in which the scientists do not fool themselves and therefore do not try to fool the public either.

Separating empirical science from dogma is a big job, and everyone with the right spirit can contribute to it. If you are a scientist, you can follow the path set by thought-leaders and those history shows were once persecuted yet eventually prevailed, to bring out the crucial information that is not widely reported because it does not fit preconceptions. You can encourage your colleagues to speak out against those who abuse their authority by using it to promote dubious recommendations as if they had been empirically confirmed.

We need people who have enough courage to say this to the low-fat dogmatists: "We're going to challenge the claims that you're making that seem to go beyond what you know."

We need to have lots of people doing just that.

What we need now is people who want to get thinking going in the right direction, not people who think they have all the answers in advance.

If we get an objective scientific process started, we can have confidence that it will bring us closer to the truth. Those preaching the low-fat dogma rely on confining their critics in a stereotype. They have learned to keep their own philosophy on the stage with no rivals allowed, and now they have to rely almost exclusively on maintaining the low-fat dogma in the cultural mindset.

The current low-fat dogma is like a great battleship afloat on the seas of evidence-based reality. The ship's sides are heavily armored with barriers to criticism, and its decks are stacked with rhetorical guns to intimidate would-be attackers. In appearance, it is impregnable - but the ship has sprung a evidence leak, and that leak widens as more and more people understand it and draw attention to the conflict between empirical science and dogma driven consensus.

The most perceptive of the ship's officers know that the ship is doomed if the leak cannot be plugged and they scramble to innundate the media with pleas to ignore the findings and data that cripple the ship. The struggle to save the ship will go on for a while, and there will even be academic rearranging of the chairs on the deck by those committed to the low-fat dogma as they remain confident the ship will not sink. In the end, the ship's great firepower and armor will only help drag it to the bottom. Reality will win.

Reality will win because the data speaks volumes.

1 comment:

  1. That was brilliant. Thanks for making my day!