You’ll note that people on these diets, including the strictest low-fat high-carb diets, significantly reduce their total amount of carbohydrates (therefore reducing the amount of insulin they secrete). The reason, I believe, most of these diets have some efficacy – at least in the short-term – is that they all reduce sugar and highly refined carbohydrate intake, either explicitly or implicitly. Someone made a great point in response to my post on why fruits and vegetables are not actually necessary for good health.
I know a lot of people who eat this way and, I’ve got to say, these folks do not eat a lot of sugar or a lot of highly refined carbohydrates. While I do plan to write an entire post on this topic of what one can and cannot conclude from an experiment, I do want to at least make the point here: The biggest single problem with nutrition “science” is that cause and effect are rarely linked correctly. I am, to be clear, not implying this is the case for this trial, but I want you to understand why it’s important to read papers fully. This trial, The Lifestyle Heart Trial, prospectively randomized a group of not-so-healthy patients into two treatment groups: the control group and the experimental group (or what we’d call the “treatment” or “intervention” group). First off, and perhaps most importantly from the standpoint of drawing conclusions, compliance was reported to be excellent and the differences between the groups were statistically significant on every metric, except total average caloric intake.
Take a moment to look over the rest of the table (or just skip reading it since I’m going to keep talking about it anyway).
Though not shown in this table, the experimental group also reported less chest pain severity (though chest pain frequency and duration were not statistically different). Let’s take a leap of faith and hypothesize that the dietary intervention (rather than, say, the social support) had the greatest impact on the measured parameters in the subjects. It’s certainly the most likely factor in my mind. But what, exactly, can I conclude?
People don’t like to be hungry, and if they are reducing their caloric intake by reducing fat intake, they seldom find themselves satiated.
Semi-starvation reduces basal metabolic rate, so your body actually adjusts to the “new” norm and slows down its rate of mobilizing internal fat stores.
I argue that reduction of fat intake has nothing to do with it and that the reduction of total calories has a transient effect. It’s *really* tough to study this stuff properly, especially compared to studying things blood pressure lowering pills, which are complex in their own right, but MUCH easier to control in a study. A nutrition department of a university accepts funds from a company that makes confectionery. Do you think the Academy’s supporters want to hear that if you eliminate their products you will no longer need to rely on the products provided by the biggest supporters of the Diabetic Association? Pretty much solely because of their report, Suzuki was forced to eventually withdraw the Samurai from production in the US although they later won the lawsuit that was filed as a result of the forged report by showing videos from the actual testing of the car conducted by CR. Ironically, the fact that CR had to admit it was faked somehow wasn’t plastered all over their magazines and the front pages of a bunch of newspapers. At that point, everything they publish became suspect and may as well line a birdcage somewhere.
Peter, I have a coworker who has recently lost 80lbs over the course of a year on weight watchers. Looking forward to your next post, and of course people's comments for the current one!
I will discuss all of this in great detail, hopefully in the coming month, when I do a post on PUFA (polyunsaturated fatty acids). Anyway, it’s nice to discover someone who takes the Taubes viewpoint on things, and also takes the time to actually post online about it with some frequency, so thanks! Oh absolutely, I was mostly referring to the fact that most of the excess carbs we eat are converted to palmitic acid, which is a SFA. There was an (1) average protein, low fat group (65% CHO), (2) High protein, low fat group , (3) Average protein, high fat, and (4) high protein, high fat (35% CHO). Thanks very much, Bob, both for the kind comments and for sharing the other data with folks.
A few weeks ago, the New York Times published an article that highlighted a study that compared the effects of a low carbohydrate and low fat diet on weight loss and cardiovascular disease risk. The results of this study drew significant media attention, and once again drew attention to the “what-should-i-be-eating-for-optimal-health” debate, which, if you’ve been following dietary trends over the past 20 years, has flip-flopped multiple times.
So while it may appear that the low-fat group experienced significant health benefits beyond the low-carb group, let’s take a closer look at the study to determine how to interpret these results properly.
Subjects in the low-fat group were instructed to eat more carbohydrates, although we know from previous studies that all carbohydrates are not created equal. Carbohydrates from grains, breads, cereals, pasta and artificial sweeteners promote more inflammation than do carbohydrates from fruits, vegetables and legumes (1–4).
Many studies have shown that high GI carbohydrates such as glucose and fructose-sweetened beverages can significantly impair these metabolic markers, whereas low GI carbohydrates from fruits, vegetables, legumes and grains have antiinflammatory effects (1,5–8).
This study is not the only study comparing low-fat and low-carb diets. There have been hundreds of previous studies comparing low-fat and low-carb diets, this study is just the recipient of significant media coverage. While some previous studies have come to similar conclusions as the current study, others have shown no difference between low-carb and low-fat diets on weight loss (9–11). More importantly, though, these studies are purely academic and do not faithfully represent conditions of free-living humans in the real world. This study demonstrates that focusing solely on the effect of fat and carbohydrate in isolation does not provide relevant information about what most people care about most: long-term and sustainable weight loss. My recommendation is simple: forget about this debate and instead focus on eating a diet containing whole, unprocessed plants. Significantly increasing your consumption of fruits and vegetables helps you achieve and maintain a healthy weight, and promotes significant health benefits beyond what can be described in a controlled research setting. And remember, before making changes to your own diet it is important to thoroughly investigate the pros and cons of limiting either fat or carbohydrate intake. There are benefits to restricting both carbohydrate and fat intake, and when making decisions about your own personal diet, be sure to read extensively and see the help of a nutrition expert in order to make educated decisions for your long-term health. Diagnosed with type 1 diabetes at the age of 22, I have spent over a decade learning the fundamentals of nutrition at the doctorate level.
That's why I've spent over 10 years developing a rock solid system that can minimize blood glucose variability and insulin resistance. That said, many of the successes (at least weight-wise, though hopefully by now you realize there is much more to health than just body composition) of popular diets can be explained by a few simple observations. You can argue that those who are overweight probably consume an even greater amount of carbohydrates. Even the Ornish diet, which is the most restrictive diet with respect to fat and most liberal with respect to carbohydrates, still reduces carbohydrate intake by about 40% from what people were likely eating pre-diet. No one on the Ornish Diet or Jenny Craig Diet is eating candy bars and potato chips, at least not if they are adhering to it. The point was, essentially, that telling people to eat 5-6 servings per day of fruits and vegetables can hopefully drive a beneficial substitution effect. I have no intention of engaging in a battle with proponents of plant-based eating or no-saturated-fat diets. Stated another way, it’s one thing to observe an outcome, but it’s quite another to conclude the actual cause of that outcome. In other words, for every intended difference between the groups a difference existed, except that on average they ate the same number of calories (though obviously from very different sources), which was not intended to be different as both groups were permitted to eat ad libitum – meaning as much as they wanted. Ornish’s study? I think the reduction in sugar and simple carbohydrates played the largest single role in the improvements experienced by the experimental group, but I can’t prove it from this study any more than one can prove a low-fat vegetarian diet is the “best” diet. We can only conclude that it’s better than eating Twinkies and potato chips which, admittedly, is a good thing to know. And, the majority of the benefit folks receive comes from the reduction of sugars and highly refined carbohydrates.
Case in point…they recently reported that olive oil is not good for you because it does not contain omega 6.
3, has a good point about some plans (including WW) having the advantage of group support, which I think is a very major confounder. It is wonderful to watch these people glow once they have found some sort of solution to their weight problem.
One of my favorite things to say to people who are scared of saturated fat is that even on an entirely plant based diet, (ala Ornish Diet), if they are restricting their caloric intake, their bodies will be running on the saturated (animal) fat that they have stored on themselves. For example the degree of unsaturated fatty acids in our membrane bilayer probably plays a role in our insulin sensitivity, just as one example.
What we do know from previous studies is that long-term sustainable weight loss is achieved by balancing energy in vs.
But for the purpose of simplicity, let’s assume even the folks who go on these diets are consuming the national average of approximately 450 grams of carbohydrate per day (in compliance with governmental recommendations, as a percent of overall intake).
If you tell someone who eats Twinkies, potato chips, and candy bars all day to eat more fruit (and they do), you’ve almost guaranteed an improvement in their health if they eat bananas and apples instead of the aforementioned junk food. I’m reasonably confident that the proponents of these diets are good people who really want to help others and have nothing but the best intentions. Ornish was the principle investigator on a trial published in the journal The Lancet in 1990. In other words, there were not enough subjects in the study to determine a difference in these “hard” outcomes, so we can’t make a conclusion about such events, only the changes in “soft” outcomes. Good science, bad interpretationGravity and insulin: the dynamic duoIf low carb eating is so effective, why are people still overweight? His clinical interests are nutrition, lipidology, endocrinology, and a few other cool things. Eg, the criticism of the Ornish Lifestyle Heart Trial is excellent (and I LOVED the kitten-stroking quip), and really could and should have stood alone.
After short diologue with her on the particulars of her daily intake I quickly realized her consumption of carbohydrate was significantly reduced and eliminated almost all fructose.
Your personal paleo code: the 3-step plan to lose weight, reverse disease, and stay fit and healthy for life. Mechanisms of disease: the role of intestinal barrier function in the pathogenesis of gastrointestinal autoimmune diseases.
Tight Junctions, Intestinal Permeability, and Autoimmunity Celiac Disease and Type 1 Diabetes Paradigms. Low to moderate sugar-sweetened beverage consumption impairs glucose and lipid metabolism and promotes inflammation in healthy young men: a randomized controlled trial. Dietary pattern analysis and biomarkers of low-grade inflammation: a systematic literature review.
Consumption of Fructose and High Fructose Corn Syrup Increase Postprandial Triglycerides, LDL-Cholesterol, and Apolipoprotein-B in Young Men and Women.
The Ratio of Macronutrients, Not Caloric Intake, Dictates Cardiometabolic Health, Aging, and Longevity in Ad Libitum-Fed Mice.
A descriptive study of individuals successful at long-term maintenance of substantial weight loss. Persons successful at long-term weight loss and maintenance continue to consume a low-energy, low-fat diet. Popularity, of course, was determined by a number of factors, including compliance with current government recommendations (sorry Atkins), number of people who have tried the diet, and reported success on the diets.
That doesn’t mean bananas and apples are “good for you” – it just means they are less “bad for you.” Here’s the kicker, though. But that doesn’t mean we can or should overlook the errors being made in drawing their conclusions. I’m not discounting soft outcomes, only pointing out the distinction for folks not familiar with them.
They never factor in that the chicken was breaded or that when someone ate steak or fish they had a large amount of bread of potatoes along with it. We’re led to believe that the reason such folks get leaner and more healthy is because they are eating more fruits or more vegetables or more grains or more [fill-in-the-blank], rather than because they eliminated the most egregious offenders from their diet. Ornish personally, and I can only assume that he is a profoundly caring physician who has dedicated his life to helping people live better lives. But as always, I STRONGLY encourage folks with access (or folks who are willing to purchase it) to read the paper in its entirety. For people who don’t want to read the study completely, or who may not have much experience reading clinical papers, I want to devote some time to digging into this paper.
The end conclusion is the whole thing must be bad and therefore needs to be reduced or outright expunged from the diet. I recall hearing Gary talking about his discussion with a participant from the Biggest loser on Larry King and the rapant weight gain after the show. It’s hard to tell if this change was statistically significant by inspection, so you glance at the p-value which tells you it was not. That is one big difference I’ve noticed between studies cited by writers who want to condemn the entire diet consumed by Americans vs those who look at it with a more in depth eye and realize that certain components are the problem not the whole diet across the board. Why did the people in the China Study who ate more plants do better than those who ate more animals (assuming they did)? Well, for starters, reading abstracts, hearing CNN headlines, or reading about studies in the NY Times doesn’t actually give you enough information to really understand if the results are applicable to you.
Parenthetically, if you actually want the answer to this question, beyond my peripheral address, below, please read Denise Minger’s categorically brilliant analysis of the study. Beyond this reason, and let me be uncharacteristically blunt, just because a study is published in a medical journal it does not imply that is worth the paper it is printed on.
Steve Rosenberg, once told me that a great number of published studies are never again cited (I forget the exact number, but it was staggering, over 50%). Translation: whatever they published was of such little value that no one ever made reference to it again. The thing is, it is possible to eliminate wheat and still eat way too many carbs (can we say ice cream?).
I’m now happily in ketosis, and the best part is, I know the WHY of weight loss now, how totally liberating and hope giving.
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