Dr. Cordain’s Rebuttal to U.S. News and World Report Top 20 Diets

Dr. Cordain's Rebuttal to U.S. News and World Report Top 20 Diets | The Paleo Diet

U.S. News & World Report ranked Paleo last of 32 diets claiming a lack of scientific evidence and no-long term weight maintenance guidelines. Are you interested in defending it or willing to provide specific refutations of their claims?

U.S. News & World Report – Health & Wellness Profile – The Paleo Diet

U.S. New & World Report – Top-Rated Diets Overall


Seth Stern

Dr. Cordain’s Response:

Hi Seth,

Good to hear from you and many thanks for your continued support of The Paleo Diet. It is obvious that whoever wrote this piece did not do their homework and has not read the peer review scientific papers which have examined contemporary diets based upon the Paleolithic food groups which shaped the genomes of our ancestors.  Accordingly the conclusions are erroneous and misleading.  I feel strongly that it is necessary to point out these errors and make this information known to a much wider audience than those reached by the readers of the U.S. News and World Report.

You have my permission to syndicate my response to any of the major news services including AP and UPI. Colleagues and scientists worldwide will receive this response to ensure that it will be widely circulated across the web and on blogs.

The writer of this article suggests that the Paleo Diet has only been scientifically tested in “one tiny study.”  This quote is incorrect as five studies (1-7); four since 2007, have experimentally tested contemporary versions of ancestral human diets and have found them to be superior to Mediterranean diets, diabetic diets and typical western diets in regards to weight loss, cardiovascular disease risk factors and risk factors for type 2 diabetes.

The first study to experimentally test diets devoid of grains, dairy and processed foods was performed by Dr. Kerin O’Dea at the University of Melbourne and published in the Journal, Diabetes in 1984 (6).  In this study Dr. O’Dea gathered together 10 middle aged Australian Aborigines who had been born in the “Outback”.  They had lived their early days primarily as hunter gatherers until they had no choice but to finally settle into a rural community with access to western goods.  Predictably, all ten subjects eventually became overweight and developed type 2 diabetes as they adopted western sedentary lifestyles in the community of Mowwanjum in the northern Kimberley region of Western Australia.  However, inherent in their upbringing was the knowledge to live and survive in this seemingly desolate land without any of the trappings of the modern world.

Dr. O’Dea requested these 10 middle aged subjects to revert to their former lives as hunter gatherers for a seven week period.  All agreed and traveled back into the isolated land from which they originated.  Their daily sustenance came only from native foods that could be foraged, hunted or gathered.  Instead of white bread, corn, sugar, powdered milk and canned foods, they began to eat the traditional fresh foods of their ancestral past: kangaroos, birds, crocodiles, turtles, shellfish, yams, figs, yabbies (freshwater crayfish), freshwater bream and bush honey.   At the experiment’s conclusion, the results were spectacular, but not altogether unexpected given what known about Paleo diets, even then.  The average weight loss in the group was 16.5 lbs; blood cholesterol dropped by 12 % and triglycerides were reduced by a whopping 72 %.  Insulin and glucose metabolism became normal, and their diabetes effectively disappeared.

The first recent study to experimentally test contemporary Paleo diets was published in 2007 (5). Dr. Lindeberg and associates placed 29 patients with type 2 diabetes and heart disease on either a Paleo diet or a Mediterranean diet based upon whole grains, low-fat dairy products, vegetables, fruits, fish, oils, and margarines.  Note that the Paleo diet excludes grains, dairy products and margarines while encouraging greater consumption of meat and fish.  After 12 weeks on either diet blood glucose tolerance (a risk factor for heart disease) improved in both groups, but was better in the Paleo dieters.  In a  2010 follow-up publication, of this same experiment the Paleo diet was shown to be more satiating on a calorie by calorie basis than the Mediterranean diet because it caused greater changes in leptin, a hormone which regulates appetite and body weight.

In the second modern study (2008) of Paleo Diets, Dr. Osterdahl and co-workers (7) put 14 healthy subjects on a Paleo diet.  After only three weeks the subjects lost weight, reduced their waist size and experienced significant reductions in blood pressure, and plasminogen activator inhibitor (a substance in blood which promotes clotting and accelerates artery clogging).  Because no control group was employed in this study, some scientists would argue that the beneficial changes might not necessarily be due to the Paleo diet.  However, a better controlled more recent experiments showed similar results.

In 2009, Dr. Frasetto and co-workers (1) put nine inactive subjects on a Paleo diet for just 10 days.  In this experiment, the Paleo diet was exactly matched in calories with the subjects’ usual diet.  Anytime people eat diets that are calorically reduced, no matter what foods are involved, they exhibit beneficial health effects.  So the beauty of this experiment was that any therapeutic changes in the subjects’ health could not be credited to reductions in calories, but rather to changes in the types of food eaten.  While on the Paleo diet either eight or all nine participants  experienced improvements in blood pressure, arterial function, insulin, total cholesterol, LDL cholesterol and triglycerides.  What is striking about this experiment is how rapidly so many markers of health improved, and that they occurred in every single patient.

In an even more convincing recent (2009) experiment, Dr. Lindeberg and colleagues (2) compared the effects of a Paleo diet to a diabetes diet generally recommended for patients with type 2 diabetes.  The diabetes diet was intended to reduce total fat by increasing whole grain bread and cereals, low fat dairy products, fruits and vegetables while restricting animal foods.   In contrast, the Paleo diet was lower in cereals, dairy products, potatoes, beans, and bakery foods but higher in fruits, vegetables, meat, and eggs compared to the diabetes diet.  The strength of this experiment was its cross over design in which all 13 diabetes patients first ate one diet for three months and then crossed over and ate the other diet for three months.  Compared to the diabetes diet, the Paleo diet resulted in improved weight loss, waist size, blood pressure, HDL cholesterol, triglycerides, blood glucose and hemoglobin A1c (a marker for long term blood glucose control).    This experiment represents the most powerful example to date of the Paleo diet’s effectiveness in treating people with serious health problems.

So, now that I have summarized the experimental evidence supporting the health and weight loss benefits of Paleo Diets, I would like to directly respond to the errors in the U.S. News and World Report article.

1. “Will you lose weight? No way to tell.”

Obviously, the author of this article did not read either the study by O’Dea (6) or the more powerful three month crossover experiment by Jonsson and colleagues (9) which demonstrated the superior weight loss potential of high protein, low glycemic load Paleo diets.  Similar results of high protein, low glycemic load diets have recently been reported in the largest randomized controlled trials ever undertaken in both adults and children.

A 2010 randomized trial involving 773 subjects and published in the New England Journal of Medicine (8) confirmed that high protein, low glycemic index diets were the most effective strategy to keep weight off.   The same beneficial effects of high protein, low glycemic index diets were dramatically demonstrated in largest nutritional trial, The DiOGenes Study (9), ever conducted in a sample of 827 children. Children assigned to low protein, high glycemic diets became significantly fatter over the 6 month experiment, whereas those overweight and obese children assigned to the high protein, low glycemic nutritional plan lost significant weight.

2. “Does it have cardiovascular benefits? Unknown.”

This comment shows just how uninformed this writer really is.  Clearly, this person hasn’t read the following papers (1 – 6) which unequivocally show the therapeutic effects of Paleo Diets upon cardiovascular risk factors.

“And all that fat would worry most experts.”

This statement represents a “scare tactic” unsubstantiated by the data.  As I, and almost the entire nutritional community,  have previously pointed out, it is not the quantity of fat which increases the risk for cardiovascular disease or cancer, or any other health problem, but rather the quality.  Contemporary Paleo Diets contain high concentrations of healthful omega 3 fatty acids, monounsaturated fatty acids and long chain polyunsaturated fatty acids that actually reduce the risk for chronic disease (10-18).

3. “Can it prevent or control diabetes? Unknown.”

Here is another example of irresponsible and biased journalism which doesn’t let the facts speak for themselves.  Obviously, the author did not read the study by O’dea (6) or Jonsson et al. (2) which showed dramatic improvements in type 2 diabetics consuming Paleo diets.

“but most diabetes experts recommend a diet that includes whole grains and dairy products.”

If the truth be known, in a randomized controlled trial, 24 8-y-old boys were asked to take 53 g of protein as milk or meat daily (19).  After only 7 days on the high milk diet, the boys became insulin resistant.  This is a condition that precedes the development of type 2 diabetes.  In contrast, In the meat-group, there was no increase in insulin and insulin resistance.  Further, in the Jonsson et al. study (2) milk and grain free diets were shown to have superior results in improving disease symptoms in type 2 diabetics.

4. “Are there health risks? Possibly. By shunning dairy and grains, you’re at risk of missing out on a lot of nutrients.”

Once again, this statement shows the writer’s ignorance and blatant disregard for the facts.  Because contemporary ancestral diets exclude processed foods, dairy and grains, they are actually more nutrient (vitamins, minerals and phytochemicals) dense than government recommended diets such as the food pyramid.    I have pointed out these facts in a paper I published in the American Journal of Nutrition in 2005 (13) along with another paper in which I analyzed the nutrient content of modern day Paleo diets (12 ).  Most nutritionists are aware that processed foods made with refined grains, sugars and vegetable oils have low concentrations of vitamins and minerals, but few realized that dairy products and whole grains contain significantly lower concentrations of the 13 vitamins and minerals most lacking in the U.S. diet compared to grass produced or free ranging meats, fish and fresh fruit and vegetables (12, 13).

“Also, if you’re not careful about making lean meat choices, you’ll quickly ratchet up your risk for heart problems.”

Actually, the most recent comprehensive meta analyses do not show fresh meat consumption whether fat or lean to be a significant risk factor for cardiovascular disease (20-25), only processed meats such as salami, bologna, bacon and sausages (20).


Loren Cordain, Ph.D., Emirates


1. Frassetto LA, Schloetter M, Mietus-Synder M, Morris RC, Jr., Sebastian A: Metabolic and physiologic improvements from consuming a paleolithic, hunter-gatherer type diet. Eur J Clin Nutr 2009.

2. Jönsson T, Granfeldt Y, Ahrén B, Branell UC, Pålsson G, Hansson A, Söderström M, Lindeberg S. Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study. Cardiovasc Diabetol. 2009;8:35

3. Jonsson T, Granfeldt Y, Erlanson-Albertsson C, Ahren B, Lindeberg S. A Paleolithic diet is more satiating per calorie than a Mediterranean-like diet in individuals with ischemic heart disease. Nutr Metab (Lond). 2010 Nov 30;7(1):85

4. Jonsson T, Ahren B, Pacini G, Sundler F, Wierup N, Steen S, Sjoberg T, Ugander M, Frostegard J, Goransson Lindeberg S: A Paleolithic diet confers higher insulin sensitivity, lower C-reactive protein and lower blood pressure than a cereal-based diet in domestic pigs. Nutr Metab (Lond) 2006, 3:39.

5. Lindeberg S, Jonsson T, Granfeldt Y, Borgstrand E, Soffman J, Sjostrom K, Ahren B: A Palaeolithic diet improves glucose tolerance more than a Mediterranean-like diet in individuals with ischaemic heart disease. Diabetologia 2007, 50(9):1795-1807.

6. O’Dea K: Marked improvement in carbohydrate and lipid metabolism in diabetic Australian aborigines after temporary reversion to traditional lifestyle. Diabetes 1984, 33(6):596-603.

7. Osterdahl M, Kocturk T, Koochek A, Wandell PE: Effects of a short-term intervention with a paleolithic diet in healthy volunteers. Eur J Clin Nutr 2008, 62(5):682-685.

8. Larsen TM, Dalskov SM, van Baak M, Jebb SA, Papadaki A, Pfeiffer AF, Martinez JA, Handjieva-Darlenska T, Kunešová M, Pihlsgård M, Stender S, Holst C, Saris WH, Astrup A; Diet, Obesity, and Genes (Diogenes) Project. Diets with high or low protein content and glycemic index for weight-loss maintenance. N Engl J Med. 2010 Nov 25;363(22):2102-13

9. Papadaki A, Linardakis M, Larsen TM, van Baak MA, Lindroos AK, Pfeiffer AF, Martinez JA, Handjieva-Darlenska T, Kunesová M, Holst C, Astrup A, Saris WH, Kafatos A; DiOGenes Study Group. The effect of protein and glycemic index on children’s body composition: the DiOGenes randomized study. Pediatrics. 2010 Nov;126(5):e1143-52

10. Cordain L. Saturated fat consumption in ancestral human diets: implications for contemporary intakes.  In: Phytochemicals, Nutrient-Gene Interactions, Meskin MS, Bidlack WR, Randolph RK (Eds.), CRC Press (Taylor & Francis Group), 2006, pp. 115-126.

11. Cordain L, Miller JB, Eaton SB, Mann N, Holt SH, Speth JD. Plant-animal subsistence ratios and macronutrient energy estimations in worldwide hunter-gatherer diets.Am J Clin Nutr. 2000 Mar;71(3):682-92.

12. Cordain L. The nutritional characteristics of a contemporary diet based upon Paleolithic food groups. J Am Nutraceut Assoc 2002; 5:15-24.

13. Cordain L, Eaton SB, Sebastian A, Mann N, Lindeberg S, Watkins BA, O’Keefe JH, Brand-Miller J. Origins and evolution of the Western diet: health implications for the 21st century. Am J Clin Nutr. 2005 Feb;81(2):341-54.

14. Kuipers RS, Luxwolda MF, Dijck-Brouwer DA, Eaton SB, Crawford MA, Cordain L, Muskiet FA. Estimated macronutrient and fatty acid intakes from an East African Paleolithic diet. Br J Nutr. 2010 Dec;104(11):1666-87.

15. Ramsden CE, Faurot KR, Carrera-Bastos P, Cordain L, De Lorgeril M, Sperling LS.Dietary fat quality and coronary heart disease prevention: a unified theory based on evolutionary, historical, global, and modern perspectives. Curr Treat Options Cardiovasc Med. 2009 Aug;11(4):289-301.

16. Cordain L, Eaton SB, Miller JB, Mann N, Hill K. The paradoxical nature of hunter-gatherer diets: meat-based, yet non-atherogenic. Eur J Clin Nutr. 2002 Mar;56 Suppl 1:S42-52

17. Cordain L, Watkins BA, Florant GL, Kelher M, Rogers L, Li Y. Fatty acid analysis of wild ruminant tissues: evolutionary implications for reducing diet-related chronic disease. Eur J Clin Nutr. 2002 Mar;56(3):181-91

18. Carrera-Bastos P, Fontes Villalba M, O’Keefe JH, Lindeberg S, Cordain L. The western diet and lifestyle and diseases of civilization. Res Rep Clin Cardiol 2011; 2: 215-235.

19. Hoppe C, Mølgaard C, Vaag A, Barkholt V, Michaelsen KF. High intakes of milk, but not meat, increase s-insulin and insulin resistance in 8-year-old boys. Eur J Clin Nutr. 2005 Mar;59(3):393-8.

20. Micha R, Wallace SK, Mozaffarian D. Red and processed meat consumption and risk of incident coronary heart disease, stroke, and diabetes mellitus: a systematic review and meta-analysis. Circulation. 2010 Jun 1;121(21):2271-83

21. Micha R, Mozaffarian D. Saturated fat and cardiometabolic risk factors, coronary heart disease, stroke, and diabetes: a fresh look at the evidence. Lipids. 2010 Oct;45(10):893-905. Epub 2010 Mar 31.

22. Mozaffarian D, Micha R, Wallace S. Effects on coronary heart disease of increasing polyunsaturated fat in place of saturated fat: a systematic review and meta-analysis of randomized controlled trials. PLoS Med. 2010 Mar 23;7(3):e1000252.

23. Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. Saturated fatty acids and risk of coronary heart disease: modulation by replacement nutrients. Curr Atheroscler Rep. 2010 Nov;12(6):384-90.

24. Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. Saturated fat, carbohydrate, and cardiovascular disease. Am J Clin Nutr. 2010 Mar;91(3):502-9

25. Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease. Am J Clin Nutr. 2010 Mar;91(3):535-46

About Loren Cordain, PhD, Professor Emeritus

Loren Cordain, PhD, Professor EmeritusDr. Loren Cordain is Professor Emeritus of the Department of Health and Exercise Science at Colorado State University in Fort Collins, Colorado. His research emphasis over the past 20 years has focused upon the evolutionary and anthropological basis for diet, health and well being in modern humans. Dr. Cordain’s scientific publications have examined the nutritional characteristics of worldwide hunter-gatherer diets as well as the nutrient composition of wild plant and animal foods consumed by foraging humans. He is the world’s leading expert on Paleolithic diets and has lectured extensively on the Paleolithic nutrition worldwide. Dr. Cordain is the author of six popular bestselling books including The Real Paleo Diet Cookbook, The Paleo Diet, The Paleo Answer, and The Paleo Diet Cookbook, summarizing his research findings.

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“20” Comments

  1. Pingback: US News Cherry Picks Diets, Arrives at Baseless Conclusions : The Paleo Diet™

  2. Hi I was doing Paleo for the past year and enjoyed every moment until recently when I was told that I have minimal plaque in two of my arteries and they also told me to give up all animal proteins which is hard to do if you’re Paleo they also told me to watch the documentary of “Forks over Knives”. In order to reverse the damage in the arteries you have to go vegan and give up all animal proteins and oils and fats completly which is very hard because I love fish and olive oil, the doctors that did the research are Dr Esylstein I hope I spelled that right and dr Ornish my question is what do you think of that documentary because I miss being Paleo thanks.

  3. 1. I like the rebuttal. My only feedback is that no one wants to be told how wrong they are. Avoiding words like “obviously…”, “uninformed” and instead just giving the facts like a computer, might help the writers change their tone.

    2. If this rating is so important, someone should set an alarm for October 2014, and email these guys every week while they’re creating this thing so they aren’t left to do it themselves. Also, loren, robb, chris, mark could send out an email to their peeps to email the news station with their own testimonials on the paleo diet. This after the fact bs never gets anywhere.

  4. Thank you Dr Cordain.

    I am a 51 year old male and have been on the Paleo/ketogenic diet for a little over six months now. My weight has gone from 178 to 165 (I’m 5’11”), and I have so much more energy and mental clarity than I have had in probably 20 years or more. What has surprised me is that I don’t have cravings for sweets, bread and pasta (all of which I loved) — in fact, I don’t really crave anything at all. I just enjoy my meals, and I feel terrific.

    It’s unfortunate that there is still so much misinformation out there about diet and nutrition, especially from medical professionals who should know better. We have to take our health into our own hands. I do not trust the medical establishment any more, certainly not with respect to diet.

  5. Pingback: 2014 Rebuttal to U.S. News and World Reports Diet Ratings | The Paleo Diet

  6. Pingback: Rebuttal to "expert" attack on Prof Tim Noakes - The Vitality Concept

  7. I've been studying paleo nutrition from an archaeological angle. The articles I have read so far indicate that more disease and dental problems cropped up when maize was introduced and became the primary caloric intake in the American continent archaeological studies I have read.

    When I stick to the paleo diet, I lose weight, need less sleep and have more energy.

    • I would say most of the dental problems came from the way they ground up the corn for flour. They crushed it between two stones. Small particles of the stone would then get mixed in with the flour. When they ate the breads made from the flour the stone particles would grind down their teeth.

  8. Someone I work with visits your site quite often and recommended it to me to read also. The writing style is excellent and the content is relevant. Thanks for the insight you provide the readers!

  9. It's just ridiculous and irresponsible that such articles get out and are published as reliable research. I have never been obese but had other issues that have completely resolved after adhering to the paleo diet – I have been living paleo for 2 years now, doing the usual 80% – 20% ratio. On the few occasions where I mistakenly had a burger or some pasta, I was so terribly sick that there's no doubt whatsoever in my mind that eating paleo is the obvious way to go. Not only do I look better that all my peers who continue to eat the "normal" western diet in Europe, the USA and Brazil, but I also feel far more energised than I have ever been when following a low-fat, high grains intake diet – I have never been a fan of junk foods or drinks, so no change there. Your diet has literally changed my world and resolved my son's skin condition, which had been misdiagnosed for 10 years. I could never thank you enough, Dr Cordain.

  10. Perhaps I'm too cynical, but I wonder if these journalists working for mainstream publications funded partly by big food industry advertising are lying to protect the sponsors. I certainly hope not. It would be horrible if these writers are putting folks at risk with their influential pens. Perhaps they are simply clueless.

  11. Beautifully written, great question and great answer! I have changed to Paleo living for the last 3 months. The Paleo diet has changed the way I live, think, eat, and enjoy life! It needs all the support it deserves!

  12. I am a lacto oval vegetarian and fined the Paleo diet interesting and informative, by excluding meat, fish, and chicken, is there a version that I can use to loose weight, improve my cholesterol levels, reduce my triglycerides, lower my A1C to below pre-diabetic status, and gain all the nutrients that my body needs to become healthier?

    • I was a vegan and there were many aspects of the diet that I benefitted from. I started having difficulty digesting wheat and grains including rice, followed by potatoes and in the end beans as well. As much as I felt I benefitted from the diet I couldn't continue without these foods. Several friends recommend the Paleo Diet to me and I can not thank them enough. I have been on it for four months and the improvements I have had in my health, weight, energy and mood have been dramatic. All I can say is try the diet for just 3 months and then decide for yourself. Three months out of a lifetime is nothing. If eating meat is hard for you then see if you can at least eat fish. The omega 3's from cold water fish are essential to your health. If this is not acceptable then look for eggs that are high in omega 3, ideally organic and from free range hens. Best of health to you!

    • @Robert Vega,

      Assuming you are eating a lacto-ovo vegetarian diet for personal moral reasons, you can still adopt a Paleo-ish approach with reasonably good results.

      What to eat: Lots of eggs, preferably pastured. A huge variety of fresh vegetables in all colors. Naturally fermented foods like whole-fat yogurt, kefir, kimchi, and sauerkraut. Lots of healthy fats such as butter, coconut oil, avocados, and olive oil.

      What to avoid: All industrial vegetable oils and processed foods. Gluten grains including whole-grain breads. Unfermented soy. Brown rice (white is ok in moderation). Definitely no fake “meat”.

      If you eat a lot of beans as a protein source, make sure to do a long pre-cook soak (at least overnight) in a few changes of water to remove as many anti-nutrients and lectins as possible.

      Finally, if you can’t eat meat, consider fish. That will open up many more opportunities for high-quality protein and healthy Omega-3 fats. Fish broth, too.

      Best of luck with your diet.

  13. Obviously the time excuse has little merit. Turn off the TV for 15 minutes and prepare a fresh meal. Not every meal has to be fine cuisine and it really only takes that long to prepare a salad and a piece of meat.

  14. They also didn't like it because you actually have to prepre the meals instead of just throwing a frozen meal into the microwave. How horrible, you might have to use a little energy to make your meal! When did we become a society so lazy we can't or won't cook our meals from scratch? I just look at cooking as a way to get a little more exercise and yes, I work full time and still make everything from scratch.

    • AMEN MELINDA! I'm just flat out amazed at how lazy people have become. I used to be one of those that ate out all the time and went for mac and cheese or hot dogs every night. Now I'm at the gym every day and doing my best to prepare every meal. My blood pressure has dropped, I have lost 60lbs, and I feel great! Next week my wife and I are starting the Paleo challenge at our Crossfit studio (60 day challenge). When they did this last time for 30 days, EVERY person lost weight, and on average they lost 3-4inches and 10lbs. I'm excited to give Paleo a try!

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