Weight loss and LC: Time to stop denying the science

I’m having a debate in a Norwegian paper with some official “nutrition experts”. They claimed that weight loss studies do not show any advantage for low carb diets. Unbelievably enough, that is what many so called experts still believe.

It’s either ignorance or science denial.

There are at least thirteen [updated:16] modern high quality trials that have shown significantly better weight loss with low carb diets. Here they are:

Randomized controlled trials showing significantly more weight loss with low carb diets


The first eleven studies in the list are weight loss trials, the last two are studies on type 2-diabetics (usually overweight) showing the same effect. Many of the studies are of six months or one year duration, one of them (Shai et al) is two years long.

All of these studies show significantly more weight loss for the group that were adviced to eat a low carb diet (Atkins, in most cases).

As far as I know the opposite has never been shown: low carb has never lost a weight loss trial significantly. This means that low carb is winning versus the failed low fat/low calorie advice by 13-0!

Feel free to let me know of any exceptions (or more examples) in the comments.

Update an expert

It’s not OK for “experts” to keep denying all these modern trials. It’s time for them to take the science seriously.

Feel free to copy or link to this list, if you encounter an expert who needs an update.

Update Jul 25, 2011

Another one, making it 14 – 0:


LCHF for beginners

Science for smart people

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  1. @Julianne

    Check the details of that study. The low-carb (their words) diet isn't low-carb, it's 40% carbs. Nor is it high-fat, it's 40% fat. Nor is it a typical low-carb diet by virtue of being hypocaloric, i.e. calorie restricted. A typical low-carb diet is at most 100g/carbs/day, or something around 20% carbs for 2,000 kcals. It's also at least 60% fat, or around 130g/fat/day for 2,000 kcals. It's also ad libitum, i.e. not calorie restricted.

    The study was probably designed to show a difference where this difference can be found.

  2. Mike
    Be aware that the Shai study essentially used an Eco-Atkins diet rather than the meaty low carb diet you promote. In the methods section, you can clearly see that the low carb group was instructed to choose vegetarian sources of protein and fat.
  3. jake3_14
    What would you think of including a reference to the meta study performed by Hession, et. al. ( http://www.ncbi.nlm.nih.gov/pubmed/18700873 and http://proteinpower.com/drmike/wp-content/uploads/2010/09/Meta-analys...) that examined the scientific literature for publications about randomized controlled trials which pitted a low-carb diet against a "low-fat and/or high-carb" diet. The researchers included only randomized controlled trials, only those which lasted at least six months, and only those whose subjects were adult and obese at the start of the experiment. (These criteria would exclude some of the papers you cite from being included in this review.)

    They found thirteen publications describing experiments that met these criteria, performed between 2000 and 2007. Most of these experiments showed a statistically-significant difference between the low-carb subjects and the other subjects, with the low-carb subjects benefiting with greater weight loss. Summing up the statistics from all of the studies showed an average (weighted mean difference) of 4 kg more weight loss among the low-carbers than among the low-fat/high-carbers at six months.

  4. jake3_14
    Does the Ebbeling et al. 2012 study (http://www.ncbi.nlm.nih.gov/pubmed/22735432) merit a reference on this page?
  5. Becky
    This is my first time pay a quick visit at
    here and i am really impressed to read everthing at single place.
  6. Nick
    Jimmy Moore didn't like the Shai et al. study and I must say he has a point. The diets weren't really reflective of the names they were given. The low carb group was actually eating 40% carbs and "counseled to choose vegetarian sources of protein and fat." Much different than the Atkins diet, wouldn't you say?
  7. Zepp
    I do like it.. at least a bit.. its more about that if peopel do eat more real food and not so scared for fat.. they get more healty!

    There are even vegan studies, and they put peopel on a vegan diet, but real food.. and they altso improve there healt!

  8. Kristin
    Dr Gardner has a presentation of his ATOZ study on youtube. Look for The Battle of the Diets: Is Anyone Winning (At Losing?). It is fabulous. I'd heard of the study but the details are worth hearing. Yes, there is a problem with the diets being insufficiently low carb but Dr Ornish also complained that his diet was also not really tested because people ate too much fat. Turns out this study also tests realistic compliance and both Atkins and Ornish diets suffered from carbs creeping up or fats creeping up. I find living low carb pretty easy unless I have to go out into the carb-soaked world so that makes sense to me. We know that Atkins kicked Ornish's hiney all over the schoolyard on that study on cv risk factors but what is not commonly known is that Dr Gardner also analyzed the results based on insulin resistance. And that is where low-carb really shines. Short story is that if you aren't insulin resistant you can choose low fat or low carb based on your personality. You have more options. If you are insulin resistant then low carb is your only effective choice. This is just some of the great stuff in that lecture.

    And for me Dr Gardner's cred goes way up in that his personal agenda was to prove low fat better (hes a long time vegetarian) but had to accept that his results did not match his preconceived notions.

  9. Janusz
    I would add to this works by Tim Noakes, which clearly show, that LCHF diet is succesfull not only in loosing weight, but also as a main diet of long distance runners and triathletes.

    I am a traithlete myself, spending anywhere between 15 to 25h a week training and my carb intake is super low ( except the long trainings e.g. 3-5hour bike rides). Not only my body fat % decreased my "goal level" (8%). It also removed food cravings (I NEED TO EAT SOMETHING NOW situations) and helped me to lose weight while gaining power (easily checked with power output tests on a bike and in a gym).

    LCHD may not be working for everyone, but it surely works for me and I'm a huge fan of it!: )


  10. Dan
    All I know is that I have been doing, this LCHF for 2 months and down 17 lbs, surger levels run from 95 to 104 and bp has dropfrpm 150/90 to 125/80. It does work.
  11. donjoe
    You do realize that every single study you've cited could just as well be considered proof that LCHP - not LCHF - diets are the most efficient for weight loss, right? And that it may in fact be the HP that allows ad libitum diets to perform better than calorie-restricted diets because of how satiating protein is and how much more caloric restriction it induces via appetite regulation.
    Reply: #62
  12. Martin Levac
    No, the A-TO-Z study shows protein intake was the same across all diets, around 20% calories. Even if the same study also shows Atkins had up to 35% protein intake during induction phase, it quickly dropped to match the other three diets.
    Reply: #63
  13. donjoe
    Nice try, but it says right in there:

    "The 4 study diets used in our study differed significantly in composition beyond carbohydrate content. Protein, fat, and saturated fat followed a continuum across diets, inverse to carbohydrate content. In a series of recent weight-loss trials that substituted either protein for fat while holding carbohydrate constant40,41 or protein for carbohydrate while holding fat constant,38,42,43 the higher-protein diets led to improvements in weight loss, triglycerides, and HDL-C and increased satiety. In the OmniHeart study, under weight-stable conditions, blood pressure–lowering benefits were observed for a high-protein relative to a high-carbohydrate diet.44 Therefore, the reported effects of the current study should be interpreted as resulting from the combination of macronutrient changes that occur when following low- vs high-carbohydrate diets, not just changes in carbohydrates alone. For example, greater satiety from the higher protein content of the Atkins diet may have contributed to the benefits observed for that group, although satiety was not assessed."

    (And BTW, the author might want to consider using this link in place of the broken link he has up there for this study.)

    Reply: #64
  14. Martin Levac
    Table 2, protein intake by % by time. All diets end up the same % at 12 months, yet Atkins continues to surpass the other three diets at 12 months. We could argue it's because of the previous 12 months of higher protein intake. But consider the difference at 2 months between highest and lowest, 27% vs 17%. Caloric intake was ~1,400 for all diets at 2 months. So, that's 94g for Atkins, 59g for Ornish. Even if we argue protein intake accounts for half the effect, that's a large effect for such a small amount of protein. Also, Ornish protein intake went _up_ at 12 months, yet did worse at 12 months than at 2 months. This fact refutes the idea that high protein intake helps weight loss. Otherwise, the increase in protein intake seen with Ornish at 12 months should make it look better than at 2 months. It also refutes the idea that such a small amount of protein could account for any large effect. Based on the results, protein intake does not offer predictive power.

    No, the greatest differences were with carbs and fat, tracking very well with the greatest differences in all things measured. The higher carbs the lower fat, the worse the outcome. Conversely, the lower carbs the higher fat, the better the outcome.

    One important note. All the diet information we're currently discussing comes from food questionnaires filled out by the subjects themselves with no supervision from the researchers. In spite of results replicating those of other dietary experiments, we cannot rely on the questionnaire information to draw conclusions about the food itself. However, we can draw conclusions about the instructions found in the respective diet _books_. In fact, since the food questionnaires were filled out by the subjects themselves with no supervision, we must see this dietary information as an _effect_ of the initial intervention. Like this: subjects write down such and such answers in the food questionnaires, because the instructions in the diet books tell them to eat such and such foods. Some diet books even instruct to keep a journal of food intake, making this food journal an explicit effect of the intervention.

    We should be discussing why the diet books themselves produce such large differences in the results. Maybe they're badly written. Maybe they're too hard to understand. Maybe they instruct to do things that don't actually work. Maybe they contain too much non-pertinent information, and this interferes with the instructions themselves. Instructions do not explain why, they explain how. How to build a house, how to assemble furniture, how to cook a pot roast, how to lose weight, etc.

    Reply: #65
  15. donjoe
    "Also, Ornish protein intake went _up_ at 12 months, yet did worse at 12 months than at 2 months. This fact refutes the idea that high protein intake helps weight loss."

    I'd have used "speaks against" rather than "refutes". You may have noticed there were 5 other studies cited in that excerpt that all supported the idea of HP being effective for weight loss. You can't just refute 5 studies based on a minor observation in another study.

    Reply: #66
  16. Martin Levac
    When a fact is true, it's always true. If it's not always true, then it could actually be false, or its truth value could depend on other variables. Why does the idea LCHP prove to be false when applied to Ornish? It could be because its truth value is low because of other variables. When we look at Atkins, we discover what these other variables are.

    But again, we're not actually discussing diets, since we have no actual information on diet.

  17. Walter
    I drank milk everyday for a month and gained 20 pounds then switched to a high carb extremely low fat diet and lost 30 pounds in 30 days. It's not about HCLF Or LCHF or LCHUDUDHHFJISOKFHBSH if you want to lose weight, just enter a state of caloric deficit. Simple. It's easier to enter a state of caloric deficit, however, on HCLF due to fat having 9 calories per gram and carbs having 4.
  18. Dr. Tariq
    I'm convinced about beneficial effects of low carb but what about high fat? I don't think these studies prove that high fat diet is beneficial. Please clarify.
    Reply: #69
  19. Peter Biörck Team Diet Doctor
    If you are convinced about Low Carb then you are almost automatically convinced about High Fat. :)

    You have to get your macronutrients from something (Carb, Protein and Fat). Even if you eat a lot of protein, I think no one would recommend that you get more than 30% of your calorie intake from that (normally it should be around 20%). And low carb means that you should get max 10% of your energy from carbs. Then the remaining energy source must be fat.

    I'm convinced about beneficial effects of low carb but what about high fat? I don't think these studies prove that high fat diet is beneficial. Please clarify.

  20. Oola
    The problem is that two years is not enough time to really tell. It is the MINIMUM amount of time necessary to see if a new eating pattern and weight will be sustainable. I'd wager that five years in, the differences would be minor. And the adherence rate would be very small. So what if a small minority of people can keep some weight off by following something very few people can adhere to?
  21. NiJo
    Weight loss is only part of the equation, surely? I don't think people should follow a diet long-term that will make them sick, which meat and dairy likely will (e.g. cancer). You don't need to replace all the carb with animal fat, use plant fat instead!
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