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The official website of Drs. Michael and Mary Dan Eades, low carb pioneers and authors of Protein Power.

Low-carb diet triumphant over low-fat in meta-analysis

I couldn’t believe my eyes when I read the paper a colleague from Europe emailed me this morning. It was from the journal Obesity Reviews, the journal of the International Association for the Study of Obesity (IASO). The IASO is the international academic obesity research society, and as such, it is mired in all the mainstream misconceptions of the causes and proper treatment of obesity. Obesity Reviews is edited by Arne Astrup, the Danish obesity researcher who is a staunch believer in and supporter of the low-fat diet as the best therapeutic tool in the battle against obesity. And Obesity Reviews is the very journal in which George Bray launched his misguided jihad against Gary Taubes and his book Good Calories, Bad Calories.

The paper, which isn’t published yet, is titled:

Systematic review of randomized controlled trials of low-carbohydrate vs. low-fat/low-calorie diets in the management of obesity and its comorbidities

The abstract of this paper pretty much says it all.

There are few studies comparing the effects of low-carbohydrate/high-protein diets with low-fat/high-carbohydrate diets for obesity and cardiovascular disease risk. This systematic review focuses on randomized controlled trials of low-carbohydrate diets compared with low-fat/low-calorie diets. Studies conducted in adult populations with mean or median body mass index of ≥28 kg m−2 were included. Thirteen electronic databases were searched and randomized controlled trials from January 2000 to March 2007 were evaluated. Trials were included if they lasted at least 6 months and assessed the weight-loss effects of low-carbohydrate diets against low-fat/low-calorie diets. For each study, data were abstracted and checked by two researchers prior to electronic data entry. The computer program Review Manager 4.2.2 was used for the data analysis. Thirteen articles met the inclusion criteria. There were significant differences between the groups for weight, high-density lipoprotein cholesterol, triacylglycerols and systolic blood pressure, favouring the low-carbohydrate diet. There was a higher attrition rate in the low-fat compared with the low-carbohydrate groups suggesting a patient preference for a low-carbohydrate/high-protein approach as opposed to the Public Health preference of a low-fat/high-carbohydrate diet. Evidence from this systematic review demonstrates that low-carbohydrate/high-protein diets are more effective at 6 months and are as effective, if not more, as low-fat diets in reducing weight and cardiovascular disease risk up to 1 year. More evidence and longer-term studies are needed to assess the long-term cardiovascular benefits from the weight loss achieved using these diets.

This is all something we long-time low-carbers have known forever, but it’s nice to see it in an international academic journal.

I haven’t gone over this paper my usual critical eye yet (I will; I just haven’t yet. I’m always suspicious of meta-analyses) for a couple of reasons. First, I wanted to get it up so that all the readers of this blog would have a chance to look it over without my input. (I found it on Scribd, so everyone can read the full text version.) And, second, because given the anti-low-carb bias of the editors of this journal, I figured that the peer-review process would have gone over it with a fine tooth comb before approving it for publication.

It will be interesting to watch what happens with this paper. The media is made aware of these papers as soon as the journal announces that they will be published. The media usually waits until right before publication or the day of publication to write articles about the paper for the general press. I will be keen to see if the media picks up on this one from this most august of academic publishers. And I’m curious to see how long it will take for Obesity Reviews to actually publish the paper in its regular journal. Often papers are put up in the soon-to-be-published or early-view sections of the online journal, but then languish there forever before actually being published. I’ll be eager to see the fate of this one.

Enjoy. Use this freely the next time your doctor or a low-carb naysayer comes at you with the old ‘Show me the evidence.’

As always, I welcome your feedback.

21 Comments

  1. Dusty on August 19, 2008 at 1:55 pm

    Predictions:
    1) IF (big if) the media actually reports on the study, the medical and scientific community will be “surprised” that such an “unhealthy diet” could have such better results in all those categories.

    2) Dean Ornish will publish an article stating how this latest study confirms what he’s been saying all along – that we agree that we should all cut refined carbohydrates and eat lots of vegetables.

    3) Joel Furhman and the PCRM crew will publish rebuttals claiming that obviously these results are only because the low-fat diets were not low-fat enough. Various vegan groups will admonish people to read The China Study so they can know just how “dangerous” meat based diets really are.

    3) Katie Couric will ask a talking nutritional head on the national nightly news that “this latest study results aside, in the end healthy eating is really just about portion control, right?”. The talking head will nod appropriately and enthusiastically.

    3) Various “authorities” will publish statements to the public warning that the long term effects on health of low carbohydrate diets are not known, so no one should start cutting carbs thinking its actually good for them.

    4) The USDA will revise its food pyramid, emphasizing “good” fats and “good” carbs, and even more whole grains.

    … and we’ll inch ever so slowly toward the medical community understanding that eating low-carb is best for optimal health…

    You’re probably right. It’ll be interesting to see how it plays out. Or if there is any press coverage of it at all.

    MRE

  2. Dusty on August 19, 2008 at 2:08 pm

    BTW and sort of on topic – did you see the Today Show segment this morning on the obesity epidemic in China? Seems that the only country with a fatter citizenry (especially children) on the planet is the good ol’ USA.

    Of course the study authors and the ‘health’ reports focused on all the fat in the fast food that is now commonplace in China. KFC took a particularly bad hit in the TV story. Nobody commented on the all the HFCS filled soda, the french fries, or the refined wheat products…

    Lao Tzu wept alongside Jesus…

    I didn’t see the segment, but I can only imagine…

  3. Ross on August 19, 2008 at 2:39 pm

    Something that annoys me is the assumption that low carb is synonymous with high-protein. We should keep protein in line with our bodies demands, but in my experience that means there’s both an upper and a lower limit on what our bodies can tolerate. For me, I can’ only handle 30-35% of calories from protein. Much more than that and my athletic performance starts to drop while my kidneys get sore.

    In my 6 months of successful low carb living, “low carb” has been synonymous with high fat and high saturated fat from whole and minimally processed sources (eggs, milk, cream, butter, cheese, pork or beef with a rind of fat, chicken with skin on, virgin coconut and red palm oils, etc.). And all the while, my blood pressure keeps dropping, my cholesterol keeps improving, my body gets leaner and more muscular, my mood stays better and brighter…

    60% calories from fat, 30% from protein, 10% from carbs. My recipe for success. Not particularly high protein, but definitely low carb.

  4. Michael Richards on August 19, 2008 at 6:25 pm

    Meanwhile, back here in the Land of Oz, scientists have discovered that humans need more protein. They made this “discovery” (made as if the Eadeses, et al, had never existed) by — wait for it —

    Analysing Locust Swarms! (Where else?)

    http://www.abc.net.au/catalyst/stories/s2069308.htm
    http://www.smh.com.au/news/national/locusts-hold-key-to-ideal-diet/2007/03/03/1172868811290.html

    Meanwhile, thanks M & MD for your lives” work. I’m sure you didn’t come up with Protein Power by observing the caterpillars and grubs in your garden. Still, if the dietary truth gets out, I guess the source is irrelevant. But what a round-about way to approach it!
    Michael

    Hey Michael–

    Simpson has been promoting a high-protein diet for years. His protein leverage hypothesis is one I talk about whenever I give talks on protein. Pretty interesting stuff. Too bad we have to rely on entomologists for reliable dietary advice instead of our own obesity experts.

    Cheers–

    MRE

  5. David MacPhail on August 19, 2008 at 6:52 pm

    Ross, I don’t think most people assume a low carb diet is high in protein. My observation is that the low fat (high carb) camp and the media seem to make a habit of stating that a low carb diet is high in protein (dangerous – bad for the kidneys!) and high in saturated fat (dangerous – bad for the heart!). And they seem to use Atkins (a dangerous crackpot!) and low carb interchangeably. After these malicious scare tactics low fat, high carb starts to look pretty good (safe!).

    Anyone who is educated about low carb eating regulates their protein requirement, keeps their carbs low and eats enough saturated fat to satiate themselves. At 60% your SFA seems on the low side. Mine tends to be closer to 75%. Anyone who thinks a low carber will gorge on fat and gain weight has never been in a ketogenic state on low carb. I find that I tend to eat modest meals and quickly reach the point where fat starts to turn me off when I have had enough.

  6. Raw Paleo Diet Guy on August 19, 2008 at 9:27 pm

    My brother is an RN and when he told his colleagues that I was on a low carb, high animal fat, Paleolithic diet, they assumed I was ignorant until he told them what my before and after blood test results were. Everything improved substantially, including my liver enzymes as well as my lipid profile. Not to mention no more hypertension! They looked at him in disbelief.

    Yes, low carb should equal high fat and moderate protein but most people do assume it to be high protein.

  7. Gordon on August 19, 2008 at 9:37 pm

    Regarding the locust articles, one of them mentioned in passing about betahistine going into trials as a “superdrug” for weight loss. Apparently they don’t understand the mechanism, but they cite one randomized trail against a placebo as demonstrating that it is very effective. It will be interesting to see how this plays out in the media and in real life. Apparently it also lowers cholesterol (I assume total cholestorol, they don’t say). The lead researcher said it made people dislike fatty foods, but I wonder if that’s real or just what they expected to see in an effective weight loss drug.

  8. Michael Kvetny on August 20, 2008 at 3:23 am

    Wow, this is great. Coming from Denmark I have always been embarrassed by professor Astrup and his sticking-to-the-fatfree-diet-no-matter-what attitude. When the Israeli study was out a month ago, he was interview for Danish TV and said that in spite of the results, he would continue to advocate the low-fat approach … inexplicably! Now, he may have to eat his hat, as the saying goes in Denmark. But will it be with a fatfree dressing or a nice creamy sauce?

    I have blogged on the issue of the new article and approached one of the major dailies … maybe they will pick up on it, though I wouldn’t hold my breath. They keep writing these little endearing pasta stories and push the official dietary guidelines, which in Denmark are just as grain-biased and warped as those from the USDA.

  9. Peter Silverman on August 20, 2008 at 4:30 am

    What one never sees is someone say: here is some low quality research that supports my view. They either see research opposing their view as worth citing, and research opposing their view as low quality.

    Not always. Here is a post yours truly did on a study showing the Atkins diet reduced the risk for colon cancer. I tries to call em as I sees em. A crappy study supporting my point of view is still a crappy study.

  10. Methuselah - Pay Now Live Later on August 20, 2008 at 4:42 am

    Obviously one of the problems with studies on diet is understanding the extent to which subjects accurately document their habits. It would be possible (though perhaps under close scrutiny not plausible) to hypothesise that different diets engender different levels of honesty. I wonder whether you know of any technologies that will, anytime soon, facilitate empirical measurement in the home where currently we rely upon testimony. I am thinking, for example, that we might be able to infer from blood samples, vital signs etc the nature of what someone has recently digested….

    No technologies that I can think of are available for at-home monitoring of honesty in sticking with a diet.

  11. Michael on August 20, 2008 at 5:13 am

    HI Michael,

    Again, thanks for keeping us updated.

    I’ve been devouring your blog for the last few months. I especially loved your blog on cognitive dissonance–which has got me looking for evidence that supports the low-carb hypothesis (which I follow, both intellectually and in practice) and the evidence which may not support it. It’s in this spirit that I would like to ask you this question (given that I am currently living in Japan)…

    How can the Japanese be dramatically thinner than almost anywhere else (everywhere else I’ve traveled) and yet they eat a lot of rice?

    My girlfriends grandmother is 98… rice is the staple of her and most of her generations diet, and Japanese live longer and are thinner than virtually another nationality.

    It’s only recently that some younger Japanese are getting fatter with the switch to greater proportion of western diets — yet Japanese are still vastly thinner than any other nationality I’ve come across. (And I lived in China at the beginning of this year, and I agree that Chinese people are totally different).

    Just a question I would love to get your input on since my girlfriend gets frustrated with me not eating rice etc… and I’ve got no argument to make given that she is super-skinny and eats tons of rice… and so are most of the other people here.

    Thanks for your input!

    Michael

    A couple of things. First, I think Asians are a little better adapted to carbs than non Asians, brought about by many thousands of years of rice consumption. Second, carbs can be consumed without all the consequences if the calories are kept low. It is my understanding that the Asian diet is pretty low-calorie as well as being high-carb.

  12. coba on August 20, 2008 at 8:02 am

    i really enjoy your site dr.,

    i moved to a very-low carb diet after reading GCBC and various sites such as yours.
    i lost about 15 pounds quickly and have plateaued some 6 months later.

    my blood work prior to the weight loss compared to after (about an 8 month time span)
    was markedly improved w/ respect to blood pressure, lower triglycerides, higher hdl and lower ldl. my liver function was unchanged w/ no indication that there was any damage or “stress” placed on my organs as a result of moving to a very low carb/high-fat diet.

    i didnt tell my family doctor until after the tests how i lost the weight and she was upset that such a diet could have “long term” implications for health. i asked her to order what ever tests she felt would be needed to examine my body and show evidence of damage that i could be doing w/ my diet, and that i would return for next years physical hopefully still on a very-low carb/high-fat diet. she agreed to this when i return and i will be one of her test subjects as she is somewhat open-minded in the face of quantitative evidence that low carb diets are not destructive (at least in the short-medium term)

    my only question is w/ respect to cravings. after over 6 months on the diet w/ only the occassional carb/dessert i still carve sweet stuff immediately after eating, even if im totally full. this craving is usually satisfied w/ a spoon of peanut butter but the only kind i enjoy does have some sugar (2-3 grams per spoon) and some transfat to stabilize it. (the natural stuff just doesnt satiate me and only makes following the diet more difficult)

    are such strong sugar cravings indicative of a flaw in my approach, or just a mental pre-occupation w/ sweets.

    any feedback would be much appreciate.

    thx

    coba

    It may be a little preoccupation with sweets, but it also may be a magnesium deficiency. I would take at least 300 mg of magnesium at bedtime and see what happens.

  13. Jim Buch on August 20, 2008 at 8:42 am

    The sponsor of the study was a commercial outfit. Lighterlife.

    http://www.lighterlife.com/how_does_lighterlife_work/foodpacks.aspx

    They sell a prepackaged 4 “meal” a day food plan which is fairly low carbohydrate and plentiful protein.

    So, the authors are, in effect, giving the low carb approach whatever agreement which published quality studies can provide.

    It’s always good to look at the sponsor or sponsors of published studies. But it’s also good to look at the actual data and how it was obtained. This isn’t the best study I’ve ever read, but it does include all the studies I’ve seen. And the criteria for study selection was pretty rigid. Usually when companies sponsor studies and the results aren’t to suit them, the end result is lack of publication. So most of the studies published showing a benefit that is also a benefit to the sponsor. Those that don’t, never see the light of day.

  14. gabe on August 20, 2008 at 8:44 am

    Another gem, thanks Mike! I just read it through before a more detailed reading but I was glad to see that this time, this meta analysis looked for more important markers of cardiovascular risk factors, such as LDL particle size instead of just plain LDL numbers. If the readers of this blog would like to compare the latest meta analysis with one published in 2006, this is the reference:

    Arch Intern Med. 2006;166:285-293

    When I read it and analyzed the data of the articles the authors chose (they used the Cochrane Research Strategy, explained in the article), it turns out that none of the studies that looked at LDL looked at particle size so the data just showed an increase in LDL, which by itself doesn’t mean squad. The conclusion of that meta analysis were:

    “Low-carbohydrate, non–energy-restricted
    diets appear to be at least as effective as low-fat, energyrestricted
    diets in inducing weight loss for up to 1 year.However,
    potential favorable changes in triglyceride and highdensity
    lipoprotein cholesterol values should be weighed
    against potential unfavorable changes in low-density lipoprotein
    cholesterol values when low-carbohydrate diets to
    induce weight loss are considered.”

    “Appear to be at least as effective as low fat… the actual studies show that the low carbohdyrate approaches (they all have a different low-carbohydrate structure, so I wouldn’t call them truly low carbohydrate but oh well…) were superior to the low fat diets. HDL improve more in the low-carb diets than it did on the low-fat diets, etc., all the improvements we all know happen on a low-carbohydrate diet. The conclusion, however, warns about the unfavorable changes in LDL (again, based on the actual number and not particle size), even though there is a lot of improvement in triglycerides, HDL and weight loss.

    The latest meta analysis is a nice breeze and I hope will get the right press. I’ve been looking for a physician in the Chicago area (any info on this will be greatly appreciated!) that is not strange to low-carb diets and wouldn’t mind monitoring me while I’m on that. I haven’t found one yet and I’ll have to settle for one that is open to ‘holistic’ approaches, rather than just medications. This meta analysis will definitely be in my briefcase when I go for my appointment.

    Hey Gabe–

    Sorry, but I don’t know any docs I can recommend in Chicago. I wish I could help.

    Cheers–

    Mike

  15. Connie on August 20, 2008 at 12:12 pm

    Chicago is the epicenter of the “Polish Atkins,” followers of Jan Kwasniewski. Perhaps you could ask around at the cafe, Calma Optimal Foods, on Milwaukee, if people have friendly docs. I wish I could go there! Wonderful ethnic food for low carb high fat.

    Thanks for the tip. I’ll remember it next time I’m in Chicago.

    Cheers–

    MRE

  16. Dusty on August 20, 2008 at 12:35 pm

    @Gabe –
    Jimmy Moore has started a resource listing of doctors unopposed to low-carb nutrition:

    http://lowcarbdoctors.blogspot.com/

    I didn’t see one in Chicago other than a Gynecologist so I am assuming you won’t need that (unless Gabe is short for Gabriella), but when you do find one send the info to Jimmy so others can benefit.

  17. peter on August 20, 2008 at 1:08 pm

    Dr. Mike,

    Did you happen to read this peice about olympic gymnasts adhering to a low-carb diet:

    http://nbcsports.msnbc.com/id/5317716/

    Now, onto a question. Why does it always seem like i have a question for you? Probably because you are a great source of knowledge and reasoning. Here goes, in a local Irish paper today, there was a snippet that said that taking heart medication with orange juice reduces the effectiveness of such medicine. Do you think there is any validity to this notion? The answer is important to me, because i have family who take heart medication.

    Best,
    Peter

    Uh, heart medication covers a lot of ground. There are only about two hundred different medicines it could be and still be heart medication. I would need to know what kind before I could comment intelligently.

  18. steve on August 21, 2008 at 3:21 pm

    not related to cake, but another reason low carb may have health benefits

    Killer Carbs – Appetite Control Cells Deteriorate As We Age, Says Study

    “A diet rich in carbohydrate and sugar that has become more and more prevalent in modern societies over the last 20-30 years has placed so much strain on our bodies that it’s leading to premature cell deterioration,” Dr Andrews said.

    http://www.scientificblogging.com/news_releases/killer_carbs_appetite_control_cells_deteriorate_as_we_age_says_study

    This comes from an interesting but pretty technical paper. Good stuff.

  19. gabe on August 24, 2008 at 6:10 am

    Mike, next time you come to Chicago, please let me know. We’d like to treat you and MD to a wonderful dining of great tapas or and Italian Steak house that has a to-die-for filet mignon! Or we might just grill in our patio!

    Thank you Connie and Dusty… a gynecologist won’t help; I’m a ‘Gabriel’ 🙂 but my wife could go there! Thanks for the suggestions.

    By the way, Mary Vernon (in Kansas) and Eric Westman (in NC), do use low carbohydrate diets as part of their practice and they also teach doctors how to use it.

    Cheers!

    I’ll take you up on it next trip to Chicago.

    Best–

    Mike

  20. Cassandra on August 25, 2008 at 2:22 pm

    More scientific evidence is comforting. But the real problem is getting people to stick to these diets once they try them. For my own part, the emotional, drug-like pull of carbs continues to suck me back, even though, having read Taubes et al, I know the damage I’m doing to my health (not to mention my waistline). Dr. Eades, what has been written on this topic, either in the popular or scientific literature? Is there anything you can recommend for people who need to make that mental switch?

    with thanks and regards,
    Cassandra

    It’s tough. Often carb cravings can often be decreased with magnesium supplementation. Maybe try 300 mg at bedtime.

  21. jeff check on November 2, 2008 at 12:35 am

    I can’t find a flaw in this study that shows low carb diets actually HURT endothelial function.

    Please help me figure out why it does not agree with your fast food comparison showing that only carbs effected endothelial heath, in this case its clearly the Low Fat not low carb diet that shows improved endothelial function.

    ———————————————————————————————-

    http://hyper.ahajournals.org/cgi/content/full/51/2/376?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=Gutterman&searchid=1&FIRSTINDEX=0&volume=51&issue=2&resourcetype=HWCIT

    Obesity is associated with impaired endothelial-dependent flow-mediated dilation, a precursor to hypertension and atherosclerosis. Although dieting generally improves cardiovascular risk factors, the direct effect of different dietary strategies on vascular endothelial function is not known. The purpose of this study was to test the hypothesis that a low-fat (LF) diet improves endothelial function compared with an isocaloric low-carbohydrate (LC) diet. Obese (n=20; body mass index: 29 to 39; mean systolic blood pressure: 107 to 125 mm Hg) and otherwise healthy volunteers were randomly assigned to either the American Heart Association modeled LF (30% fat calories) diet or an isocaloric LC Atkins’ style diet (20 g of carbohydrates) for 6 weeks (4-week weight loss and 2-week maintenance phase). Brachial flow-mediated dilation and dilation to nitroglycerin were measured with ultrasound using automated edge detection technology (baseline, week 2, and week 6). Blood pressure, weight loss, and cholesterol profiles were measured throughout the study. Weight loss was similar in LF (100±4 to 96.1±4 kg; P (95.4±4 to 89.7±4 kg; P pressure decreased similarly in both groups (LF: 8/5 mm Hg; LC: 12/6 mm Hg) at 6 weeks. After 6 weeks, the percentage of flow-mediated dilation improved (1.9±0.8; P<0.05) in the LF diet but was reduced in the LC diet (–1.4±0.6; P panels was similar at 0, 2, and 6 weeks. Despite similar degrees of weight loss and changes blood pressure, LF diets improved brachial artery flow-mediated dilation over LC diets. LF diets may confer greater cardiovascular protection than LC diets.

    I read this study when it first came out. I didn’t put a whole lot of stock in it because of the small number of participants and the fact that the actual diets used weren’t presented. I’d like to know a little more than that one group went on an Atkins diet while the other went on an AHA-type diet. According to the paper, these subjects all got their food from the study center, so it would have been easy to describe the diets better. I’m always a little wary of studies showing an unexpected effect when the authors decide not to include an important part of the data. This missing factor tells us something about the peer-review process where low-carb diets are concerned. I’ll guarantee you that if this study had shown the opposite effect, the peer-reviewers would have insisted that the individual diets be described. But since the study confirms the bias of most reviewers, they didn’t ask that it be included. Another thing that got my antennae up were the differences in caloric intake at the start and at maintenance. According to the study, the group randomized to the LC diet was consuming significantly fewer calories than the members of the group randomized to LF. The LF group cut more calories during the 4 wk weight loss phase than did the LC group, then during maintenance the caloric intake of the LF group didn’t go as high as it was pre-study whereas the LC group went higher. It doesn’t make sense to me how this could happen. It also doesn’t make sense that subjects on a LC diet of 20g CHO per day could eat that many calories, which is why it would have been nice to have seen the actual food choices.

    Another problem with this study is the group of people looked at. They are a different group indeed, as even the authors admit. These are obese people with none of the typical lab findings of obesity and/or insulin resistance. Look at the triglyceride numbers alone. Obese people with triglycerides of 77 are unusual. What applies to these people may not apply to the typical obese person.

    But, even if we assume that the study were perfectly done (ignoring the fact that there were a tiny number of subjects), it is only one study. And as I’ve said countless times, one study doesn’t prove anything. It would have to be repeated again and again before one could say definitively that LC diets made endothelial function worse.

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