Mainstream medicine’s latest multimillion dollar effort to prove the effectiveness of the low-calorie, low-fat diet once again blew up in their collective faces, but that’s not what this post is about. This post is about how mainstream medicine deals with data it doesn’t like. How instead of presenting the data for what it is, mainstream medicine tries desperately to sweep its failures under the rug.
Despite not showing what their authors want them to show, the important point about these ‘failed’ studies is that they move science forward. They sometimes nullify dearly held theories, which is exactly what scientists are supposed to want to do.
Sadly, all too often, scientists (who should know better) fall in love with an hypothesis and set up an experiment to confirm it instead of trying to falsify it. Then when their machinations fail and the experiment is a bust, they try to put a good face on and make like the experiment really showed what they wanted it to show all along.
Just as there is no doubt a bias in the mainstream news media, sad to say, there is also a bias in the mainstream medical scientific media.
Most academic nutritional researchers hold two progressions near and dear to their hearts.
Eating saturated fat —> elevated cholesterol —> heart disease.
Exercise plus cutting calories and fat —> weight loss —> a longer, healthier life
The first of those progressions is known as the lipid hypothesis; the second is the eat less, move more hypothesis.
If any part of one of the above equations breaks down, then the whole thing falls apart. So God forbid that anyone should make the case that any segment of the above pathways doesn’t hold up to scrutiny. Should that happen, the infidel needs to be prepared to pay the price.
How do these infidels pay the price? Usually by having their data and/or their conclusions attacked in the very same journal in which their study was published.
Typically, when important studies are published, the editors of the publishing journal recruit someone in the field to write an editorial about the study. Depending upon what the study in question showed and the bias of the particular journal, the editorial can be positive or negative. Unfortunately, more researchers/doctors read the editorial than read the actual paper. So, more often than not, the editorial is what spreads the word. If the study has an outcome that flies in the face of the editorial writer’s bias, you can bet that the editorial will be a denunciation. Or sometimes, the editorial will even make it seem as if the paper showed a different outcome than it really did.
Let’s look at an example.
A couple of years ago, Ron Krauss, as mainstream a researcher as you could find and holder of all sorts of academic credentials, started thinking that maybe saturated fat wasn’t the demon everyone thought it was. He dug up all the studies he could find looking at whether or not saturated fat actually did cause heart disease. He put all these studies together in a meta-analysis, and got it published in the prestigious American Journal of Clinical Nutrition (AJCN). The article, titled Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease, came to the following conclusion:
there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD. More data are needed to elucidate whether CVD risks are likely to be influenced by the specific nutrients used to replace saturated fat.
And, as if to rub salt in the wounds of the lipid hypothesis folks, Krauss published another paper in the same issue of the same journal looking at a nutrient that often replaces saturated fat.
This second paper, titled Saturated fat, carbohydrate, and cardiovascular disease, concluded
there are few epidemiologic or clinical trial data to support a benefit of replacing saturated fat with carbohydrate. Furthermore, particularly given the differential effects of dietary saturated fats and carbohydrates on concentrations of larger and smaller LDL particles, respectively, dietary efforts to improve the increasing burden of CVD risk associated with atherogenic dyslipidemia should primarily emphasize the limitation of refined carbohydrate intakes and a reduction in excess adiposity.
As you might imagine, the mainstream lot didn’t take this lying down.
The very first article in this issue of AJCN is an editorial by Jeremiah Stammler, a low-fatter of the deepest dye and one of the scientists who worked in Ancel Keys’ lab throughout his years of fighting to establish the lipid hypothesis. The Stammler piece, Diet-heart: a problematic revisit, is the editorial equivalent of foaming at the mouth. Here’s a sample so you can see what I mean.
Coupled with the statement in the Abstract and Conclusions in the meta-analysis (2), ‘‘there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD,’’ the authors seem to be dissociating themselves from prevailing national and international dietary recommendations to the general population for primordial, primary, and secondary prevention of CHD/CVD and the established major metabolic risk factors. But they are not explicit. Is that their intent? Specifically, do they disagree with the merits of heart-healthy fare on the basis of DASH-, OmniHeart-, Mediterranean-, East Asian–type eating patterns, which emphasize vegetables, fruit, whole grains, legumes/seeds/nuts, fat-free/ low-fat dairy products, fish/shellfish, lean poultry, egg whites, seed oils in moderation, alcohol (if desired) in moderation, and portion size/calorie controlled and deemphasize red and processed meats, cheeses, ice cream, egg yolks, cookies/pastries/ pies/cakes/other sweets/sweetened beverages, snacks, and salt/ commercial foods with added salt. Estimated nutrient composition of this fare is as follows: total fat ’20–25% of kcal, SFA 6– 7%, MUFA 7–9%, PUFA 7–9%, cholesterol ,100 mg/1000 kcal, total protein 18–25%, vegetable protein 9–12%, carbohydrate 55–60% (mostly complex), fiber 30–35 g/d, 50–65 mmol Na/d (2900–3770 mg NaCl/d), mineral/vitamin intake high (6). A vast array of concordant multidisciplinary research evidence is the sound foundation for these recommendations.
See what I mean? And it goes on and on in this same vein. As in, the data be damned. How can these guys have the temerity to go against all these recommendations we’ve spent years coming up with?
The average doc picking up this copy of the AJCN might take a look at this editorial first and then may not even bother reading the actual studies.
Unfortunately, this happens all too often.
The Stammler editorial is the attack kind of editorial. But as I mentioned before, there is another kind. One even more treacherous, because it pretends the study says something it doesn’t. People don’t recognize the editorial as a polemic, so don’t get their critical faculties involved and often accept it at face value.
Recently the New England Journal of Medicine published the results of the Look AHEAD study in an article that pretty much put paid to the ‘low-calorie, low-fat diet along with exercise’ as the optimal therapeutic modality for diabetics. (Several years back the Women’s Health Initiative did the same thing for women without diabetes – but that study seems to have been forgotten by the mainstream crowd.)
Here is the set up. The study, published as Cardiovascular Effects of Intensive Lifestyle Intervention in Type 2 Diabetes, randomized 5145 obese, diabetic subjects into two groups, one of which underwent intensive lifestyle modification with all kinds of hands-on care, up to and including adding weight loss drugs if the lifestyle modification didn’t work. The other group, the control group, had a few educational sessions about diabetes.
The lifestyle intervention group was encouraged to commit to 25 minutes of moderate intensity exercise daily and to follow a low-calorie, low-fat, low-saturated fat diet. If interested, you can read the entire Look AHEAD protocol (click the link and go to study protocol) to see for yourself the extent to which the researchers went to make this study work. And as I mentioned above, going to the extreme of giving the interventional subjects weight-loss drugs if the diet and exercise didn’t work.
The study was designed to run 11.5 years with the following conditions being end points:
Death from cardiovascular causes
Nonfatal myocardial infarction (heart attack)
The study authors felt strongly that within the 11.5 years enough subjects would suffer one of the above endpoints to show a statistically significant difference between the lifestyle intervention group and the control group. Their hope, of course, was that the intervention group would live on while the control group died like flies, proving the efficacy of the eat-less, move-more philosophy so near and dear to their mainstream hearts.
It didn’t quite work out that way.
As the years dragged on and the control subjects refused to die or suffer any of the other endpoints at greater rates than the intervention group, the researchers decided to change the stakes.
They increased the length of the study to 13.5 years, figuring, I suppose, if we let it run on long enough, the damn controls should finally start kicking off. And to goose it even a little more, they added another endpoint: hospitalization for angina (chest pain of cardiac origin).
At the 9.6 year mark, the endpoints reached in the control group were not statistically different from those in the lifestyle intervention group. The study was stopped on the basis of a futility analysis. In other words, the writing was on the wall. There was not going to be a major difference between the two groups, so why continue spending money in a futile effort.
The abstract of the study pretty much says it all.
The intervention group lost more weight, which is pretty much proof they adhered to their diets (or took their weight loss drugs). And
the intensive lifestyle intervention also produced greater reductions in glycated hemoglobin and greater initial improvements in fitness and all cardiovascular risk factors, except for low-density-lipoprotein cholesterol levels.
Which is interesting, because it also shows they stuck with their exercise regimens and their diet. The decreased LDL is the give away. LDL levels always go down on low-fat diets. (But as readers of this blog know, that’s far from the whole story.)
So, subjects who followed the low-fat, low-calorie diet and exercised at moderate intensity for 175 minutes per week did as hoped. They lost a little weight and improved some fitness parameters, but they didn’t avoid the serious outcomes any better than the couch potatoes did.
Remember the hypothesis from earlier:
Exercise plus cutting calories and fat —> weight loss —> a longer, healthier life
The eat less, move more therapy brought about weight loss but no difference in ultimate outcome. So
Exercise plus cutting calories and fat —> weight loss -X-> a longer, healthier life
What we can say from this study is that diabetics, who are on an accelerated aging trajectory, did lose weight on a low-fat, high-carb, low-calorie diet and moderate intensity exercise program. But they did not live longer, healthier lives.
We can’t say what would have happened had these subjects been on low-carb diets because those diets weren’t studied. As you might imagine, I have my own ideas, but the results aren’t known because that study wasn’t done.
In large long-term studies such as this one, it’s common for researchers to carve out certain subgroups within the greater group of study subjects and look at other outcomes. Which they did in this case and found that some of the subjects in the intensive lifestyle intervention improved in some of these other outcomes as compared to their control counterparts. But, the group as a whole didn’t die at lower rates or have any fewer serious problems.
The Look AHEAD study was an expensive, high-profile undertaking involving 216 centers all over the United States. It was a flop. So, you would expect an accompanying editorial to such a study, and you wouldn’t be disappointed.
The editorial, Do Lifestyle Changes Reduce Serious Outcomes in Diabetics?, appeared in the same issue of the NEJM.
The simple (and correct) answer to the question the title asks is no.
But the author doesn’t see it that way. He ends the editorial on a high note, pretending that the study kicked tail. He tells doctors that the results of the study empower them to go out and recommend these same lifestyle modifications to all their diabetic patients.
Don’t believe me?
Here is concluding paragraph:
Clinicians can now use the results of the Look AHEAD study, as well as the group’s previously published findings, to inform their care of patients with diabetes. They can clearly assert that changes in activity and diet safely reduce weight, reduce the need for and cost of medications, reduce the rate of sleep apnea, improve well-being, and (in some cases) achieve a diabetes remission. With respect to cardiovascular outcomes, inspection of the confidence intervals should allow clinicians to reassure their patients that intensive lifestyle interventions are unlikely to cause harm (i.e., the upper limit of the hazard ratio for the primary outcome was 1.09) and may provide a modest benefit. However, even with no clear evidence of cardiovascular benefit, the Look AHEAD investigators have shown that attention to activity and diet can safely reduce the burden of diabetes and have reaffirmed the importance of lifestyle approaches as one of the foundations of modern diabetes care.
And have reaffirmed the importance of lifestyle approaches as one of the foundations of modern diabetes care?!?!
Remember, doctors are busy, and they often just skim the actual studies and read the editorials instead. I’ll leave it to you to draw your conclusions as to the message a busy physician would take away from this editorial.