Science and Low Carb / Paleo

This page summarizes some of the science behind low carb / paleo diets.

Bottom line

The latest review of all major trials of low carb diets show improved weight AND improvement of all major risk factors for heart disease:

Saturated fat

Saturated fat

Despite half a century of research there is still no evidence that natural saturated fat (like butter, eggs etc.) is anything but completely safe to eat.

Have a look at these recent reviews of all the evidence:

Insufficient evidence of association is present for intake of … saturated or polyunsaturated fatty acids; total fat … meat, eggs and milk.

There were no clear effects of dietary fat changes on total mortality or cardiovascular mortality…

no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD.

But wait, what about butter and other high fat dairy specifically? Well, actually people consuming it are if anything thinner and healthier than others:

The observational evidence does not support the hypothesis that dairy fat or high-fat dairy foods contribute to obesity or cardiometabolic risk…

This means that the scientific foundation of the low fat dietary advice has fallen. The reasons for it today are mainly economical (low fat high sugar products are very lucrative and finances a lot of lobbying), combined with old-fashioned prestige and inertia.

The low fat dietary advice has become a house of cards with nothing to support it. It is just a question of time before it’s apparent to everybody.

Heart disease

Two years of advice to follow a very low carb and high fat diet reduces atherosclerosis:

Weight loss

Weight loss

Some people still claim 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 18 modern scientific studies of the highest quality (RCT) that show significantly better weight loss with low carb diets:

RCTs showing significantly more weight loss with low carb diets

  1. Shai I, et al. Weight loss with a low-carbohydrate, mediterranean, or low-fat diet. N Engl J Med 2008;359(3);229–41.
  2. Gardner CD, et al. Comparison of the Atkins, Zone, Ornish, and learn Diets for Change in Weight and Related Risk Factors Among Overweight Premenopausal Women. The a to z Weight Loss Study: A Randomized Trial. JAMA. 2007;297:969–977.
  3. Brehm BJ, et al. A Randomized Trial Comparing a Very Low Carbohydrate Diet and a Calorie-Restricted Low Fat Diet on Body Weight and Cardiovascular Risk Factors in Healthy Women. J Clin Endocrinol Metab 2003;88:1617–1623.
  4. Samaha FF, et al. A Low-Carbohydrate as Compared with a Low-Fat Diet in Severe Obesity. N Engl J Med 2003;348:2074–81.
  5. Sondike SB, et al. Effects of a low-carbohydrate diet on weight loss and cardiovascular risk factor in overweight adolescents. J Pediatr. 2003 Mar;142(3):253–8.
  6. Aude YW, et al. The National Cholesterol Education Program Diet vs a Diet Lower in Carbohydrates and Higher in Protein and Monounsaturated Fat. A Randomized Trial. Arch Intern Med. 2004;164:2141–2146.
  7. Volek JS, et al. Comparison of energy-restricted very low-carbohydrate and low-fat diets on weight loss and body composition in overweight men and women. Nutrition & Metabolism 2004, 1:13.
  8. Yancy WS Jr, et al. A Low-Carbohydrate, Ketogenic Diet versus a Low-Fat Diet To Treat Obesity and Hyperlipidemia. A Randomized, Controlled Trial. Ann Intern Med. 2004;140:769–777.
  9. Nichols-Richardsson SM, et al. Perceived Hunger Is Lower and Weight Loss Is Greater in Overweight Premenopausal Women Consuming a Low-Carbohydrate/High- Protein vs High-Carbohydrate/Low-Fat Diet. J Am Diet Assoc. 2005;105:1433–1437.
  10. Krebs NF, et al. Efficacy and Safety of a High Protein, Low Carbohydrate Diet for Weight Loss in Severely Obese Adolescents. J Pediatr 2010;157:252-8.
  11. Summer SS, et al. Adiponectin Changes in Relation to the Macronutrient Composition of a Weight-Loss DietObesity (Silver Spring). 2011 Mar 31. [Epub ahead of print]
  12. Halyburton AK, et al. Low- and high-carbohydrate weight-loss diets have similar effects on mood but not cognitive performance. Am J Clin Nutr 2007;86:580–7.
  13. Dyson PA, et al. A low-carbohydrate diet is more effective in reducing body weight than healthy eating in both diabetic and non-diabetic subjects. Diabet Med. 2007 Dec;24(12):1430-5.
  14. Keogh JB, et al. Effects of weight loss from a very-low-carbohydrate diet on endothelial function and markers of cardiovascular disease risk in subjects with abdominal obesity. Am J Clin Nutr 2008;87:567–76.
  15. Volek JS, et al. Carbohydrate Restriction has a More Favorable Impact on the Metabolic Syndrome than a Low Fat Diet. Lipids 2009;44:297–309.
  16. Partsalaki I, et al. Metabolic impact of a ketogenic diet compared to a hypocaloric diet in obese children and adolescents. J Pediatr Endocrinol Metab. 2012;25(7-8):697-704.
  17. Daly ME, et al. Short-term effects of severe dietary carbohydrate-restriction advice in Type 2 diabetes–a randomized controlled trial. Diabet Med. 2006 Jan;23(1):15–20.
  18. Westman EC, et al. The effect of a low-carbohydrate, ketogenic diet versus a low- glycemic index diet on glycemic control in type 2 diabetes mellitus. Nutr. Metab (Lond.)2008 Dec 19;5:36.

The first 16 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 advised 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 18-0!

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.

The science of low carb

Here is the opinion of a true expert on low carb diets, dr Eric C. Westman, MD and president elect of the ASBP (weight loss doctors):


LCHF for beginners

Science for smart people

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  1. Zepp
    There is verry.. verry litle chanse that you wake up one morning and look like Arnold Swatsenegger!

    It takes a lot more exercise and probably some anabolic steroids?

    The only thing that ordinary people do get is better strenght and a better fysical capability.. verry seldom a real muscle growht!

  2. @Martin
    thanx for that. I will continue to exercise, but not with that expectation. I have been on a ketosis diet for four months now and I am seeing great results.
  3. @Zepp
    thanks for the response. I have been reading this site for a month now and will ask more questions knowing I can get answers.
  4. my second question has to do with "long term ketosis diets" because I read an article saying you cannot maintain LCHF diets over time due to bad long term effects. I have read of other people being on low carbs for many years so I tend to see that article as FUD. Any comments?
  5. @eddacker

    There's tons of websites and blogs for low-carb and ketosis. My favorite, the one I visit most often, is In fact, that's where I heard about Andreas Eenfeldt and LCHF in Sweden, and basically all other websites and blogs about low-carb I visit. It's primarily a forum, but there's also tons of info about studies, history of low-carb, etc. If you visit the forum, be sure to check out the media/research sub-forum. That's where all the current news about low-carb is posted. You can also check out the various sub-forums dedicated to specific diets like Atkins, Protein Power, etc. Even if you don't visit that forum, this here is one of the top low-carb blogs in my opinion. You're already in the right place.

  6. I have just very recently been introduced to this website, and the philosophy behind it, and I can say that already, I have noticed some results that were unexpected. Primarily in how I feel. My mood has improved, and I feel clearer mentally. As a Dallas Therapist, I help people with mood problems, and I am interested in continuing to learn about how diet plays into this. I hope to learn enough that I can help my clients with using diet as a possible intervention.
  7. Nice comment; I too have noticed an improved attitude and more energy, it is a great bonus to the physical benefits for my T2 diabetes and weight loss/maintenance.
    There are several great commenters here and they can give you good guidance.
  8. Gout is related to red meats and or too much protein. You likely were eating too much protein and not enough fat nor fibre. Switch to organ meats, or switch to white meats, eat a lot more fat and a lot less protein, and try again.
  9. @forevernade
    gads, I hate pork, I can only eat so much. being American I love beef.
    But never 'lean' always with a dose of fat or full fat choices. Cooked in Olive oil of course.
    Bacon is an exception. And I still have lots of salad with mayo, nuts and seeds. Watching my protein and getting my energy from fat.
  10. @forevernade

    Gout is not related to red meat, nor any kind of meat, nor protein. It's caused by sugar, most likely fructose. It's also caused or at least exacerbated by alcohol. Look up fructose metabolism, and you'll find out all about gout. It's also strongly associated with diseases caused by carbohydrate poisoning; obesity, diabetes, hypertension.

    I understand the hypothesis that says an amino acid - purine - can convert to uric acid, which can then lead to gout. But the problem with this hypothesis is that gout occurs independently of uric acid blood level. You can have low uric acid and still get gout. You can have high uric acid blood level and never get gout. Half the cases of gout occur with low uric acid, the other half with high uric acid.

    This idea that meat is somehow involved in disease must stop. It makes no sense that for over 2 million years meat was our staple food therefore kept us in good health, yet in the last 30 years meat has become the death of us. The half-baked hypotheses about the causes of gout tell me the experts don't really know, so they're not really experts.

  11. john
    I love meat
  12. FRAN
    salt= would it be ok if your body is going very faint and ill feel.. like having natural hot dogs and bacon..
  13. What does anybody think about this article in today's Guardian Weekend about what doctors would never do. One is that they would never follow a low-carb diet (scroll down on the link here to find the relevant section). They refer to a study of 43,396 Swedish women who were followed for an average of 15 years that found that those who stuck to low carbs and high protein had a rising risk of dying from heart attacks and strokes - 'a staggering 62% higher risk'. That's unfortunately bad advertising for the low-carb diet. I suspect the study has many flaws - I certainly hope so.

    Reply: #65
  14. I've just seen this post by Mark Sisson, so it looks as if the maths was wrong:

  15. Thank you Ted.
  16. Liam
    I think all the risks for heart disease and cardio attacks the low carb diet is still successful is applied by many people to lose weight. To avoid the risks we need to go through the criteria like the pros and cons of the diet because at last our body is going to take all these change or experiments.
  17. Fred
    This site does not promote a low carb high protein diet. It is a low carb high fat diet. Get it right.
  18. Ed
    Several of the links on this page are dead, and the first link to the meta-analysis only points to the abstract. It once pointed to the full study.
    Reply: #70
  19. Perhaps if you emailed someone they'd let you read a copy if you didn't save it when it was available.
  20. If you ever want to take some of the load off, I'd really like to write some material for your blog in exchange for a link back to mine. Please send me an e-mail if interested. Regards!|
  21. Gary
    I understand that Fred, but how can you have a low-carb diet without significant protein(unless you eat like a bird). I could never stay on a low carb diet eating only rabbit food. Ive been off an on the low carb diets since about 1976 and have had no shortage of protein. I am still alive and kicking.
    Reply: #73
  22. Zepp
    Well Gary, we recomending the same amount of protein as FDA, WHO, SLV, Fineli.. what ever!

    Soo.. to say this is a high protein diet one have to reject all the goverment and all nutrient knowledge about essentiall amino acids!

    Its a high fat diet.. IE, a ketogenic diet!

    You know, even vegans have there need of essential aminoacids, its the same for us.. the differens is they take it from vegetable sources.. we eat meat/fish/egg/poultry/dairys!

    Protein is not that good as fuel.. its more a boulding stone in our bodys!

  23. Ed
    >>>I could never stay on a low carb diet eating only rabbit food.

    Generally, rabbit food is not low carbs.

    Rabbit as a food is.

    The key is to eat plenty of fat, no carbs and not seek high protein foods. If you eat the protein that naturally occurs in meat with fat, you'll probably get enough but not too much.


  24. Gareth Hicks
    Hi, I was recently introduced to your site - and have watched most/all of the videos and read most of the info - and comments. Wow ! Lifechanging for me !!

    Like just about everyone else on here, LCHF has been a revelation to me. I was a massive fruit eater - who suffered with very bad arthritis (I had a hip replacement by the time I was 45). I am probably 20lb overweight, not exercising much, and was eating a 'healthy' diet of fruit for breakfast, sandwich for lunch and a paleo dinner.

    I've changed my eating habits to incorporate LCHF for about a month and have lost about 4Kg through water-loss so far, and am feeling energised, happy and very well. However, I have two quick questions, if I may:
    1. I do still drink about 3 or 4 glasses (maybe upto 750ml) of very dry white cava most evenings, in a social setting. I recognise that this isn't ideal, and I'm working away from it - in the interim could you let me know what problems it causes to drink very dry wine (with minimal sugar) whilst on the LCHF ? I have noticed that it increases my desire for chocolate after I have had a glass or two - but I can resist those urges !!
    2. I have taken Barley Grass as a supplement daily for about 2 years. At the moment, my desire for vegetables and other greens is greatly diminished. Is it ok for me to continue to take Barley Grass - and/or will my desire for non animal fat based foods return?

    Thanks - and thanks to all the commenters on here too - it's been a life changing event for me to find an eating regime that I can adopt long term that is healthy, balanced - and makes me feel so well. I love it - and I'm losing weight - what's not to like ;)

    Reply: #76
  25. Zepp
    Let it take the time it needs to get in to new eating habits.. mayby you dont need to cut out everything from your past!

    That about wine and such a thing is more about if one can handel it.. nothing perticuly for a LCHF living!

    Mayby if one cut out everything thats not real food one can lose a pound or soo.. thats what its all about.. but one have a life to live altso.

    Couldnt be more then fibers and water in Barley grass??

  26. Gareth Hicks
    Thanks Zepp - it's almost like a prescription to keep drinking ;) lol

    I was having a non-citric fruit smoothie every morning which I suspect was creating havoc with my insulin production and was keeping me chubby ;( I'm happy with the ongoing weightloss: all in good time - and the change in eating habits is making me feel very well. I'm only eating when hungry - and mostly having animal fat products.

    I'm still having about 50-100gms of carbs from rice or bread, fried in fat I make from making beef stock dripping as well as loads of eggs, cheese, cream products. I was panicking about my cholesterol level, as it was 'high' last year - and I'm due a check in May - however, I have watched a video today:
    that continues to add fuel to my fire that the things I am doing to change my life are going in the right direction. I will, however, be booking a 'particle' blood test to check my cholesterol again against my new understanding.

    Your website and the philosophy you have shared is inspiriational ! I'm very excited to be on this journey and will report back in a few months !
    Thanks loads, it's been very liberating so far ;)

    Reply: #78
  27. Zepp
    Well, I regard you as a grown up.. so you should alredy know about benefits and side effects of alkohol!

    Its more about if you want to get in extra high ketosis or similar that one need to be an ascetic one!

    And you know.. the french do eat a lot of saturated fat and drink wine.. they dont get that much hart attacks!

    Soo.. mayby you could call it a mediteranian diet.. french style?

    Its always a good idea to check ones healt markers.. and there are a few that not tollerate high fat altso.. but they are rare.. and they supose to know about this alredy.. becuse one or both of there parents do have that condition too.

  28. Jack Brookes
    I am a student and I am designing a graphic booklet that shows the vaste evidence supporting low carb diets, even if it can be called a diet. I have lived this way for about a year now, I'm healthier and have no cravings for snacks. It is a little hard to eat in London when they're are so many foods containing carbs. I end up going to a Asda or Tesco and buying ready cooked meat.

    I do lots of sport and was wondering is there another way to gain muslce mass and weight.

    I simply have a LCHF diet for 5-7 days then 1-2 days of LFHC to gain wieght.

    is there any other way on protein and fat to put on weight.


  29. @Jack Brookes

    I'm no expert but I think I can give you a few ideas. Gary Taubes wrote a book Good Calories Bad Calories. In that book, he makes the argument that fat tissue is regulated by hormones. So, if that's true, then what regulates _muscle_ tissue? Once you figure that out, you'll be able to design a proper muscle-building program.

    I mean, if I wanted to design a proper _fat_ building program (you know: grow fatter!), I'd start by eating more carbs. :)

  30. es
    >>So, if that's true, then what regulates _muscle_ tissue? Once you figure that out, you'll be able to design a proper muscle-building program.

    It's not that simple. Insulin is the hormone that regulates fat storage, and that's an entirely different process from building muscle. I know of two books that are dedicated to this topic: "The Smarter Science of Slim" by Jonathan Bailor and "The Art and Science of Low Carb Performance" by Phinney and Voleck.

    I also recommend Taubes "Good Calories Bad Calories" but I prefer his newer book "Why we get Fat"

    All are on Amazon, bug GCBC may be available only as a used book.



    Reply: #82
  31. @ "bug GCBC may be available only as a used book."
    It's was sold in UK as The Diet Delusion which is available on kindle or as a paperback edition.
    The Diet Delusion [Kindle Edition]
    Reply: #84
  32. @es

    I asked "what regulates muscle tissue", just as Taubes asked "what regulates fat tissue". That's where we start with building muscle. It's that simple. Consider the question Jack asked "is there any other way on protein and fat to put on weight". It's the wrong question because it implies that "protein and fat" is the cause, and "put on weight" is the effect. But my question "what regulates muscle tissue" does not assume an already established cause-and-effect. It _asks_ what the cause and effect is.

    Do you believe the bodybuilding world knows how it works? On one side, you got the regular Joes who are told to eat more to grow, eat less to cut, and lift weights in a million different ways. On the other side, you got pro bodybuilders who inject T/GH/IN/IGF/MGF/etc all the while telling the world they grow big by lifting heavy. Truth is pros grow big because of hormones, and they can lift heavy because they're big. Fact: Growth hormone causes muscle growth all on its own without a single weight lifted. It does this through various ways, some of which are growth factors called myostatin and follistatin. Breeding manipulations of genetic traits directly related to those two growth factors in beef produced the Belgian Blue, which has about double the muscle mass, i.e. double the meat.

    Ask the right questions. Get the right answers. Don't assume anything. It's that simple.

  33. Thanks, Ted, a very 'time-saving' comment.
  34. TK
    I am looking to start a low carb diet for a weight loss problem.

    My concern has been ateroesclerosis if a high fat diet does not cause this then what does?

    Why are so many people are having bypasses?

    This is my concern that is holding me back I am not saying that any of this is wrong I just need more convincing before I start a LC Diet that's all.

    Reply: #86
  35. Zepp
    Well to be frank.. some few have problems with fat, they have a genetic disturbance cald Familiar Hyperlipedemia.. but you should be knowing if you have this!?

    The moste others that have Aterosklerosis problem becuse of Metabolic syndrome.. I.E.. its about glucose metabolism!

    "Methods and Results— To represent the progressive stages in the natural history of type 2 diabetes mellitus, we stratified 134 individuals (age 45±12 years) into 1 of 4 groups: (1) lean normoglycemic (lean), (2) overweight and obese normoglycemic (obese), (3) impaired glucose tolerance, and (4) type 2 diabetes mellitus. Localized 1H magnetic resonance spectroscopy and cardiac magnetic resonance imaging were used to quantify myocardial triglyceride content and left ventricular function, respectively. Compared with lean subjects, myocardial triglyceride content was 2.3-fold higher in those with impaired glucose tolerance and 2.1-fold higher in those with type 2 diabetes mellitus (P<0.05). Left ventricular ejection fraction was normal and comparable across all groups.

    Conclusions— In humans, impaired glucose tolerance is accompanied by cardiac steatosis, which precedes the onset of type 2 diabetes mellitus and left ventricular systolic dysfunction. Thus, lipid overstorage in human cardiac myocytes is an early manifestation in the pathogenesis of type 2 diabetes mellitus and is evident in the absence of heart failure."

  36. es
    >>I am looking to start a low carb diet for a weight loss problem.

    That's the best option for most people.

    >>My concern has been ateroesclerosis if a high fat diet does not cause this then what does?

    Carbs, mostly. The major risk factors for CVD are low HDL; high TG; high small dense LDL particles; high blood pressure.

    All of those improve dramatically for most people on a LCHF diet.

    >>Why are so many people are having bypasses?

    Because most people eat a high carb diet that makes everyone of those risk factors worse.

    >>This is my concern that is holding me back I am not saying that any of this is wrong I just need more convincing before I start a LC Diet that's all.

    Check out the studies on the web site, specifically the very first one and the random controlled trials. Look at the impact of diet on the risk factors for CVD.


    Reply: #174
  37. 1 comment removed
  38. Sofi
    I'm wondering if any of the women trying this approach to eating as seen a difference in cellulite? I'm 5'5 and weight about 152 lbs, workout a lot, running, lifting weights and still have an aweful amount of cellulite. I've tried Atkins before but get bored fast and did not see any difference on the amount of cellulite....just wondering if anyone would be willing to share their knowledge/experience on this subject. Thankyo !
  39. Sophie
    Cellulite is a media invention of the first half of the 20th century. It was more or less brought up by Vogue in the 60s!

    Cellulite is just fat accumulated in specific areas.

    There are no huge differences between LCHF and Atkins. If you got bored with it and did not follow it, you should not be surprised it did not reduce your adipose tissue.

    Unfortunately we don't get to decide where we lose the fat. Also, whatever fat cells you have on you are part of your body forever! When you lose weight, the fat cells lose the fat that they contain, but they remain on you nonetheless.

    Fat is fat, cellulite is just localized fat. I lost fat by sticking to my low carb diet. It's very slow. I don't think it's really worth trying unless you are dedicated to do whatever it takes to reach your goal, but that's just me.

    But low carb absolutely worked to decrease the fat I have on me.

  40. qhfgva
    I'm trying to develop a habit of looking into references more carefully. Above you have:

    There were no clear effects of dietary fat changes on total mortality or cardiovascular mortality…

    Hooper L, et al. Reduced or modified dietary fat for preventing cardiovascular disease. Cochrane Database Syst Rev. 2011 Jul 6;(7):CD002137.

    But the first line of the results says:

    This updated review suggested that reducing saturated fat by reducing and/or modifying dietary fat reduced the risk of cardiovascular events by 14%

    This seems to be saying the opposite. Am I missing something?

  41. Zepp
    It says you got a higher risk.. but you dont die of it! ;)

    And then.. whats the higher risk.. probably biomarkers as cholesterol and such a thing?

    Soo.. is those biomarkers dangerus at all??

  42. Mike
    Dear Doctor Diet,

    I think there is a lot of science supporting LCHF for the average person but what about people with Familial Hypercholesteremia (specifically the heterozygous sort)? As this is a liver gene defect which creates abnormally high cholesterol in it's sufferers, do you still recommend LCHF to these patients as well? With FH, modifying the diet has a small effect but not enough and nearly all sufferers of this genetic disease must take statins to bring the cholesterol down to safer levels.

    I would be nervous to suggest to someone with FH to eat steak with Bernais sauce every day as well as egg yolks for breakfast every morning with butter. What are you thoughts Doc?

    Reply: #94
  43. Zepp
    Mike.. you know there is a lot of different genetic, allergic and other dysfunctions!

    And I dont think there is a good idea for those how have a real FH to rely on a high fat diet.. at least not without cheking there lipids and how its progress!

    You know.. its a lot about those with FH and extrapolation from those that give us the fear for fat.. but thats only a misconception.. its the wrong conclusion!

    And now the moste problem is the metabolic syndrome.. how have a strong link to glucose metabolism.

    Soo.. what its all about.. its about to eat real healty food.. and avoid anyting that is unhealty or that you have a genetic dysfunction to metabolise.

  44. Wendy
    I had a very brief read of this post and decided to click the Cochrane review article "Reduced or modified dietary fat for preventing cardiovascular disease" knowing Coochrane Reviews have the highest level of evidence.

    If I selectively read the article I would see your "There were no clear effects of dietary fat changes on total mortality or cardiovascular mortality" HOWEVER Science is not about selecting lines from an article to suit you and misleading people to believe the opposite of what is suggested by the artlcle.

    If I were to chose a line I would chose it from the conclusion: "Lifestyle advice to all those at risk of cardiovascular disease and to lower risk population groups, should continue to include permanent reduction of dietary saturated fat and partial replacement by unsaturates."

    Also note from the results section: "This updated review suggested that reducing saturated fat by reducing and/or modifying dietary fat reduced the risk of cardiovascular events by 14%"

  45. Zepp
    Strange.. one could reduce saturated fat, and get a lower risk.. then, the risk is non.. so how do you make that sounds?
  46. @Wendy

    Your post implies the following assumption: If it's true for the group, then it must also be true for individuals in that group.

    Since we're talking about studies, then the equivalent is: If it's true for a group of studies, then it must also be true for individual studies in that group.

    This is just an assumption, which means we must check the individual studies to see if our assumption is correct. When we start with the Cochrane study, then check individual studies - as those in the blog post above - we find our assumption is not correct. So what's the problem?

    Either our selection of individual studies is biased, or the group of studies is biased. The answer is in the "Selection Criteria" of the Cochrane review: "2) intention to reduce or modify fat or cholesterol intake (excluding exclusively omega-3 fat interventions)". This is "intention to treat".

    In scientific studies, the term "intention to treat" means there's no data, but they still assumed there was, so they estimated whatever data was missing, and included this estimation in the results. In other words, they made it up. You could say it's a valid way to find results. I don't. I prefer to consider only hard data. So I ignore any study/review which includes intention-to-treat as a selection criteria or protocol. Unfortunately, this means I should ignore the Cochrane review. And I do ignore it.

    In fact, I should ignore the Cochrane review because one of the parameters which justifies intention-to-treat is lack of compliance, and compliance is one the most significant factor for success with dietary intervention. In other words, a diet works as long as we actually do it. In the A-TO-Z study for example, we see that the Atkins group was the most compliant, and also showed the best results. Conversely, success/failure is also a significant factor for compliance, which suggests that compliance was higher with Atkins because it was more successful.

  47. Zepp
    Well I shouldnt ignore the Cochrane study.. read the data.. ignore there conclusions.. I can draw my own conclusions.. shouldnt wee?

    They didnt find any clear effects from reducing fat.. that says me a lot more then there own conclusions.. they couldnt fins anything in the data.. but draw some off topic conclusions anyway!

  48. ES
    >>There were no clear effects of dietary fat changes on total mortality or cardiovascular mortality…

    >>This updated review suggested that reducing saturated fat by reducing and/or modifying dietary fat reduced the risk of cardiovascular events by 14%

    >This seems to be saying the opposite. Am I missing something?

    Two different measures: Risk for cardiac events and mortality. Reducing saturated fat did not reduce mortality.

    As for the risk for cardiac events, it's important to note this: "Subgrouping suggested that this reduction in cardiovascular events was seen in studies of fat modification (not reduction - which related directly to the degree of effect on serum total and LDL cholesterol and triglycerides"

    What this suggests is that the risks for caridac events is directly related to LDL and triglycerides. As the bulk of the studies on this page show, a LCHF diet improves blood profile, lowering triglycerides, lowering small LDL and increasing HDL.

    It seems clear that reducing saturated fat, while not changing carbohydrate intake does not reduce mortality.

    >>>Science is not about selecting lines from an article to suit you and misleading people to believe the opposite of what is suggested by the artlcle.
    >>>If I were to chose a line I would chose it from the conclusion: "Lifestyle advice to all those at risk of cardiovascular disease and to lower risk population groups, should continue to include permanent reduction of dietary saturated fat and partial replacement by unsaturates."

    But that's not science. That's not data and that's not results. That is simply the opinion of the author.

    One of the key arguments made by LCHF diet proponents is that there is a bias in medical and research communities against fat and saturated fat (and in favor of carbs) that is not supported by the evidence. The researchers' conclusions, especially in light of the weak correlations, are perfectly consistent with the suggestion of an unscientific bias.


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