Unrestricted Low-Carb Diet Wins Hands Down

Steak SaladThe New England Journal of Medicine has just come out with perhaps the most definitive comparison of low-fat, Mediterranean and low-carb diets ever, and the findings dovetail very nicely with what we’ve been discussing here recently about the merits of the Primal Blueprint. I think it also addresses some of the concerns shared about the so-called “restrictiveness” of my PB plan.

This study looked at over 300 people who followed their assigned diets strictly for two years, making this one of the longest diet studies in recent history. The bottom line was that the low-carb diet was hands-down the most impressive at improving health in all areas. Those on the low-carb plan lost more weight, experienced a greater reduction in the dangerous C-reactive protein, lowered their triglycerides, raised their HDL cholesterol and dropped their A1C more than those on either the Mediterranean or the low-fat diets, although the Mediterranean was a close second most of the time. Of course, for those who read MDA religiously, you’ll be interested to hear that the low-fat diet was “restricted” to only 1500 calories per day for women and 1800 for men, as was the Mediterranean diet, but the low-carb diet was “unrestricted”, meaning those participants could eat all they wanted of non-carb foods (fat and protein, people). They started out at only 20 grams carbs a day for two months, then eased up to 120 grams a day maintenance at the end. Compliance was fairly high, too: of the 109 people assigned to the low-carb plan, 85 finished the entire two years.

For those of you asking for more “evidence” that the way Grok ate was healthful, I can now add this study to the ever-increasing body of work. Of course, we here at MDA can speculate (and do we ever) on why carbs are not-so-great from purely a gene-expression POV, on why fats are our “healthy friends” from an evolutionary biology perspective and why proteins should form the basis of a fat-burning, muscle-building Primal eating program. But it sure helps that a study like this – with zero attachment to any evolutionary rationale – comes up with a parallel conclusion. This quote is taken from the paper:

The similar caloric deficit achieved in all diet groups suggests that a low-carbohydrate, non–restricted-calorie diet may be optimal for those who will not follow a restricted-calorie dietary regimen.

When will guys like Dean Ornish and John MacDougal realize they have gone way too far down the wrong low-fat path?

joshbousel Flickr Photo (CC)

Further Reading:

Definitive Guide: The Primal Blueprint

Mark Sisson is Not Afraid of Fat

The Context of Calories

Definitive Guide to Fat

The Best Low-Carb Fruits (and Worst)

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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41 thoughts on “Unrestricted Low-Carb Diet Wins Hands Down”

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  1. From the study:

    The present study has several limitations. We enrolled few women; however, we observed a significant interaction between the effects of diet group and sex on weight loss (women tended to lose more weight on the Mediterranean diet), and this difference between men and women was also reflected in the changes in leptin levels. This possible sex-specific difference should be explored in further studies.

  2. “They started out at only 20 grams carbs a day for two months, then eased up to 120 grams a day maintenance at the end.”

    Could you explain what this carb maintenance is all about? Is it unhealthy to routinely eat under 50 grams of carbs?

  3. “The intakes of total calories, protein, and fat were not limited. However, the participants were counseled to choose vegetarian sources of fat and protein and to avoid trans fat.”

    Hmm. . . What’s with recommending vegetarian sources?

  4. Neal Barnard has already commented that the so-called “low-fat” diet was 30% fat, close to the SAD and far greater than the 10% advocated by Ornish and Esselstyn. In fact, most studies on “low-fat” diets allow participants to consume about the same percentage of fat calories as this one. I am not a low-fat advocate, but I think the diet debate can only be settled when a low-carb whole foods diet is pitted against a low-fat whole foods diet, not some slightly modified version of the SAD.

  5. The report I have read said that this was a modified Atkins diet where they got their fat from fish and vegetable oils, not meat and dairy. I still think PBers can take this as good news, but as Sonagi suggested, the ultimate study hasn’t been done. Gary Taubes said in his book that it would be terribly expensive to do what really needs to be done to settle this.

  6. Will, yeah, it’s unfortunate that only 10 women started the low-carb part (and we don’t know how many finished). I would have loved to have seen more women in the overall study (and especially low-carb) but it was done within a group of one company’s employees in Israel, most of whom were either men, or most of whom were overweight men.

    As Dave says, it’s a start. I’d love to be able to fund a full on PB versus the extreme low-fat of Ornish. Until then, this moves in the right direction.

  7. Mark
    Here’s another quote from the second to last paragraph which dovetail’s nicely with your “Context of Calories” post:
    “The results imply that dietary composition modifies metabolic biomarkers in addition to leading to weight loss.”
    Gene expression matters. Nice to see the evidence

  8. I spent an hour reading different news stories about this, as well as viewing video reports from NBC and CBS. It’s hard to believe that all these reports are talking about the same study! I thought the reporter on NBC was the most positive about the report and fended off a suggestion that the study was biased because it was partially funded by Atkins. You can find the video online on MSNBC site.

  9. Very nice that you can view the full report as a pdf which can be saved for future reference.

    One thing that really amazed me was the chart on page 238. Apparently, participants lost weight steadily on the low-carb plan during the 2 month induction phase where carbs were limited to 20 gr a day.

    But after that, when carbs were slowly brought up to 120 gr a day, during the so-called maintenance phase, participants slowly and consistently regained weight.

    It makes me wonder if they started to binge or sneak extra carbs once the daily limit rose from the initial period. One of the big problems with this type of study is that it is dependent on the participants being honest about their behavior.

  10. I wonder if the subjects self reported being satiated on the mediterranean and low-fat diets. 1800 calories seems ridiculously low for somebody like me (age 25, bmi 22), but I suppose that as I get older, I’ll probably naturally want to consume fewer calories (mean age in this study is 52, bmi 31)

    The fasting glucose graph among diabetics is really strange. Although the sample size for diabetics is only 36, it’s really remarkable that at 12 months, the low carb yielded lower fasting glucose, but this all reverted in the next year.

  11. That was a Good Study. I think Mc Dougall and Ornish HAVE to be seeing the writing on the wall as this point…However I’d love to see the Fuhrman Eat to live program Studied. Fuhrman Limits grains significantly, and Stays away from Sat/Trans/Poly Fats as well. His book is well referenced.

  12. It is also noteworthy that total fat intake in the low carb group was 40% as was the CHO intake. Apart from calorie intake the changes seem to have been minor and much less than I presume most of the readers of this blog achieve.

  13. Interesting that people on these low carb blogs say that you can’t lose weight on a low fat/high carb diet but this study proves that isn’t true. The low fat people lost close to 5K and the low carb lost a little more than 6K at the 5 month mark. At the end of the trial, med and low carb were more or less the same.

    –4.4±6.0 kg for the Mediterranean-diet group, and –4.7±6.5 kg for the low-carbohydrate group

  14. First off Mark, I love your site. Not disputing that, however…

    Your comment above ‘the low-carb diet was hands-down the most impressive at improving health in all areas’ isn’t exactly an accurate reflection of what the study found. In terms of weight loss alone there is an interaction between time and weight when the diet type is considered as a factor but the significant differences between diets compares specifically the med and low-carb to the low-fat group. There appears to be no significant differences in weight lost between Med and low-carb here and given the sex interaction they found, they actually show that med is better if you are female.

    The type of diet didn’t have a significant effect on reduction in waist circumference or diastolic or systolic blood pressure.

    In the blood panel, diet type did have an effect but post hoc test results were not carried out between all groups. They compare both the Med diet and the Low-carb diet separately with the low-fat and while the low-carb comes out with a statistically significant difference (not, of course to be confused with biologically significant) between the low fat, at no time is the Med diet compared statistically with the low carb diet. If there is no significance there (and for some of the items it looks superficially like there may not be) then there is really no reason to believe that the tables wouldn’t be turned the other way if we repeated that study a couple times.

    This isn’t a shortfall of the study but a reflection of the aims of the study. They set out to see if the Med and Low-carb could be deemed as effective/safe or better than the low fat diet typically used in a clinical setting. A different analysis would be needed to talk about the supremacy of one of the two and it doesn’t look like that would have come out with a definitive answer (maybe why they chose to publish the findings this way) 😉

    This is getting long but there are similar findings in the metabolic markers they consider.

    The paper itself has the most concise summary of what the study does and does not try to establish.
    ‘We found that the Mediterranean and low-carbohydrate diets are effective alternatives to the low-fat diet for weight loss and appear to be just as safe as the low-fat diet.’

    It is a bit of a stretch to go beyond that. This is a bit of a pet peeve of mine where science journalism is concerned so I really wanted to add my two cents. I apologize for making the comment so long. I think it gives the dark side (aka low fatties) less fuel when we stick to accurate unbiased interpretations of the available science and these guys just weren’t interested in a comparison between Med and low-carb.

    As you point out above, for those that find it hard to stick to a restricted diet, the low carb folks basically self controlled their Caloric intake, they ate the same level of Calories as the others.

    I think that’s cool because I’m much more easily satisfied on less food eating like Grok!

  15. Looks like Michael and Joe have good points. Low carbers ate a bit more protein and fat and only about 10% less carbs on average than the others and Med ate more Fibre than the others. Apart from that there are almost NO significant differences in the dietary compositional breakdown. Also quite a few more low carbers dropped out. So I suppose it helps with dietary adherence provided that you tolerate it in the first place.

    I would love to see a proper study done that combines the high fiber of Med diet with higher fat and protein of the low carb. I’d go into that one with the prediction that the effects would be synergistic and that it would come out very well against the others!

  16. I always loved the mediterranean diet, being portuguese it’s also cultural to me. More recently i’ve started the low carb diet and the results were even better. both diets are for sure the best ones.

  17. While the the results may be impressive, I’m not putting all my apples in this particular basket. I believe that grains are an important aspect to any diet, eliminating them altogether in order to loose weight is a misnomer. Healthy eating combined with proper exercise will certainly produce positive results. Your culture, genetics, and lifestyle determine what your body composition will be; not some fad diet.

    Change your mindset. Don’t be a follower, be a leader. Do what works for you and be happy. 🙂

    1. I’ve always been of the belief that if you ate healthy and exercised, one could lose wait. But when that didn’t happen, I blamed it on genetics. I’ve never followed any “diet” until 2 months ago. I started South Beach Diet after a friend recommended, although I was a bit wary of the “diet” tag. I lost weight in the first phase but as soon as I reintroduced the whole grains in the second phase, my weight went up. I didn’t understand what was happening, so I went back to phase 1, voila, I lost weight again. And that prompted me to google low-carb diets and that’s how I landed on MDA. I’m doing Primal and my weight, nay, my body fat is dropping.

  18. A quote on the study from The New York Times:

    “Women fared best on the Mediterranean diet, losing about 14 pounds compared with about 5 pounds on the low-carbohydrate plan.”

    That isn’t exactly what I would call low-carb winning hands down.

  19. Nathalie:

    I believe that grains are an important aspect to any diet

    Why? What makes you believe that? Grains are a blip on the evolutionary food radar. What makes them “important” (other than the government tellin you so via the food pyramid)?

    eliminating them altogether in order to loose weight is a misnomer

    I’m not sure how this is a “misnomer” but if you think that the suggestion to eliminate grains is solely for the purpose of weight loss, then there are several posts here you should read–starting with the first link included in this post (the Primal Blueprint).

  20. I’m sorry, but this study shows very little. First, the total weight loss was only 10 pounds over TWO YEARS! And all the weight was lost in the first year – from months 12 to 24 there was no change in weight for low-carb.

    The subjects in this study started as “moderately obese” and then lost only 10 pounds. And how will they lose any more weight if they’ve made no progress from months 12 to 24?

    If anything, this study shows that diets in general, including low-carb, are ineffective in helping a person achieve a normal weight.

  21. From a health writer’s blog on the NY Times website:

    “I’m troubled at the way this is being reported. This was not a clear victory for the Atkins diet by any stretch, although the researchers tried to present it that way. I’ve added a link to the post with comments from Dr. Ornish. In my view, the Mediterranean diet had the edge in this study, but the reality is that none of them was very successful.”


  22. Anything that gives a plug for low-carb, low-grain is a step in the right direction. This isn’t the first study, there have been many.

    The only true study is the one we do on ourselves. Right? One-two months guality protien, fat, green vegetables, nuts, etc.

  23. As I have stated on other blogs, I would have much preferred to see a true low carb vs true low fat comparison (because these weren’t exactly extreme versions of either), but this will have to do for now. Too bad they allowed the carbs to bump to 120 after 2 months. These were fairly overweight people who had a lot more to lose if they wanted to, so could have held at 20-50 grams carbs a day for a lot longer. The initial weight loss was far more impressive in the low carb group. I think the bloodwork shows the greatest advantages in low carb. The next advantage is the “ad libitum” feature of the low carb program. Finally, I would love to get my hands on the individual stats. Of the 109 people that started in the low carb group only 10 were women and we don’t know how many women actually finished.

  24. Anything that gives a plug for low-carb, low-grain is a step in the right direction.

    No, it isn’t. A big, big problem with research studies is that they are often funded by vested interests and designed to yield a particular outcome. The media adds to the problem with misleading headlines and omission of key details. Fundamentalism isn’t good in religion, health, or anything else. People and science have been proven wrong time and time again, so the big idea in this story isn’t low-fat versus low-carb but reading critically and keeping an open mind.

  25. Sonagi-
    Again, study, research, experiment and come to your own conclusions.
    Yes, you’re right about the funding/media. Since I KNOW that eating a low carb diet is healthy, I don’t care who funded it this time around.

  26. Mark, great site.

    The low-carb group failed miserably at trying to keep at a max of 120 grams per day (as instructed to do so by the researchers). They did succeed in lowering their carbs less than the other diets however. On average the low-carb group got 40% of the energy from carbs!!! (see table 2) That means if they ate on average 2000 calories per day, that comes out to 200 grams of carbs per day. I think the results are encouraging. Their results would have been much better if they would of really stuck to the low-carb diet.

  27. I agree with Mark. I’d really love to see a truely low fat diet studied along with a truely low carb diet.

    But this study is still very important. The essential message is this: You can eat semi low fat, count calories, be hungry and lose some weight. Or you can eat a mediterranean diet, count calories, be hungry and lose a bit more weight. Or, finally, you can eat just a slightly low-carb diet, eat all you want, never be hungry, and lose even MORE weight.

    That’s a pretty powerful message for somebody who wants to lose weight but hates counting calories and feeling hungry.

  28. I get what you are saying Binko but what I was hoping to get across is that the last part of that is very much NOT what the study is saying. It just isn’t.

    It is important that we don’t buy what the media tells us when they just plain get the science wrong because next month someone will come out with a contradictory study and somewhere in the world thousands of people will decide that scientists can’t get their story straight and aren’t worth listening to at all.

    Not even dealing with the fact that this study went no where near the idea of how satiated the subjects “felt”, I feel the need to repeat that the Mediterranean and Low-Carb diet groups did NOT lose a different amount of weight. I know that the average losses make it look that way but the SCIENCE is simply not there. Interpreting as has been done here and on the news report last night is, unfortunately, a real problem where credibility is concerned.

    I agree that it could be a powerful message if that were the message but I am afraid that is not correct. The study is good because now a person who doesn’t want to follow a low fat calorie controlled diet might have a chance of convincing an up to date, well informed and evidence-based dietitian that a low-carb Calorie unrestricted diet is a viable option. That much is true.

  29. Considering the study was partially funded by the Atkins foundation, I’d take the results with a grain of salt. Junkfood science does a good job ripping this so-called science apart, here.

  30. Don’t get fat, and live physically active and you don’t have to mess with diets such as this one, or any diets which change your eating habits because your unhappy with your gut or cellulite.

  31. Mark – First, love the blog. But I’ve noticed that you haven’t responded to the comments regarding the misleading headline about low carb winning hands down, and your post that followed. I think that this is an important mistake to acknowledge and a lesson to learn. One can, and should, only be taken seriously as a health writer and reporter if one refrains from over the top and unsupported statements in an attempt to prove a point, such as the above. The women, few as they may have been, did indeed do better on the Med. diet. And the men had only slightly better results on the low carb over the Med.

    Not to speak for your audience, but as a whole I believe that we trust what you report, and I myself would like to continue believing that you will give science precedence over personal opinion (meaning obviously taking every study with a grain of salt, but at least reporting on it correctly).

  32. But where do you find out what you should and should not eat? There are tons of diet books out there but are they telling you the correct way?

  33. Well, this is all very confusing I think. The Med diet is very good but is probably a temptation to far for people who consider themselves ‘carb addicts’. Mediteraneans do not fill up on the same types of carb junk as some of us do either. And they eat a lot of low carb stuff such as olives, artichokes, cheese, fish, small amounts of meat, and veg/fruit, and olive oil etc. So although not specifically low carb, the diet is probably in the acceptable range if followed properly. The Mediteraneans that I’ve seen do not stuff their faces with pizza, fries, burgers (in a bun), and so on – not routinely anyway. Plus their diet is not specifically low fat – they do like their oil.

    I’m trying to stick to this Primal low carb as best I can, averaging around 100 to 120g carbs a day but sometimes less and sometimes more (being veggie it’s hard to reduce much more without real hunger)but I feel better with cutting down significantly on the carbs as they tend to bloat me.

    I must be doing the Primal Med diet 🙂 as it seems to be a mix of the two, and it seems to be working as I feel a bit lighter and less bloated.

    I think that, unless you live outside of society, it is very difficult to stick with any strict regime for any length of time and I suspect a lot of the people in the diet trial just lacked discipline in the end which may explain why they stabilised in year 2, and why they didn’t lose much in year 1 it seems. A trial is probably better conducted by observing people who have changed their diet because they wanted to and adopt an ‘eating plan for life’. So ignore the Weight Watchers, Slimming Worlds, Atkins etc, as most of these people could be adopting a fad diet attitude. That’s why more than 95% of ‘successful’ dieters end up piling it back on again, because they haven’t really changed their attitude to food (stats often quoted).

    Sorry for rambling on so much.

  34. A los carb unrestricted diet is the only thing that has given me lasting results – ideal body weight, maximum energy and after the initial discomfort – absolutely no cravings. Great study, thanks for highlighting this in your post

  35. Guys
    i have been on a a low carb diet for close on 2 years , most of that time on less than 20 grams a day. the weight loss has been great…but, i notice that after prolonged periods at below 20 grams i start to battle with conversation , not being able to find the right words in the middle of a sentance etc.when this occurs i increase my carb intake and a few days later i can feel the differance. i have searched on line , and cant find anyone that has similar symptons. am i alone on this?

  36. How about we think about how humanity grew up on proteins/fat/saturated fat/cholesterol 35,000 years ago? Agriculture is the bad guy here. I understand why humans created it roughly 10,000 years ago to provide food when food wasn’t available in ample supply. There were no McDonalds providing bad food, no deep fried french fries, no super sweet Wendy’s milkshakes that are a high blood pressure event for a week for me. Humans were a LOT healthier then based on my experience with PB. I am pretty much on a fat/protein deal with the Primal Blueprint and all of my blood work (cholesterol, LDL, HDL, etc including blood pressure were in amazing ranges) for the first time in about 8 years for me. That is how long I was taking blood pressure meds, and then for the last two years I was taking testosterone injections (I currently do not take either medicine now and haven’t for about 8 months now) Thank you Mark for providing what you do for your site and I hope you know you’ve changed more lives than you’ll probably ever know about. I have had 2 friends who have switched to PB in the last two-three months and one of them has lost a belt loop hole in size within the first 30 days. I guess it helps that I have my super slim figure with very little gut remaining and I am now exercising almost daily with resistance and strength training (no cardio as that ages us faster). People have seen changes over the last year and they like what they see. I’ve probably done more exercise in the last 45 days than I have done in the past 10 years.

    Thanks again Mark, for your contribution to humanity in providing the information and your website. As far as I’m concerned, you are my “hero”.

  37. Hi Mark,
    I am doing this low Carb thing (2weeks) after the past 6 months on the low fat restricted cals plan. Worked really well and lost 13kg (28 lb) and decided to start the low carb plan to get the last few kg off as I am very close to my goal weight of 125lb. We are now looking at it as a ‘long healthy life’ way of eating not for weight loss any more (we are a doctor and nurse so love the science). I do restrict my cals per day from 1300-1500 on this plan (habit) and work on a ration of 55% fats/ 30% protein and <20% carb. I do permit grain in the form of a low carb bread (4 net carb per slice- 3 slices max per day) but that is it for grains. Cut out all bad oils etc and got back to basics re food.
    -Have I got it right re the low carb % ratios?? its about <60 gms per day.
    -I have not had a great deal of weight loss yet but will it happen??? We are also getting into more weight excersisis and ultamate frisbe is being planned.
    – Want to ensure the low carb bread I am eating is not defeating the goal! and I like that it gives me lots of fibre too….
    We are very passionate about this way of eating- we are from NZ and are fast catching up to the USA as the fattest country!!
    Thanks Di

  38. This is a nice blog on weight loss. Thank you for sharing this topic and I’ll be thankful to you for give me this opportunity to give my views on this .Keep writing.