Paleo Magic?

Click me! To see study.

This study is making the rounds of the paleosphere, so I thought I’d take a moment to look into it and see if it lives up to it’s claims that a paleo-‘type’ diet ‘has strong and tissue-specific effects on ectopic lipid deposition in postmenopausal women’ (‘ectopic lipid deposition’ = fat deposits on organs and skeletal muscles).

I got my hands on the full text and had a look. Quick synopsis: researchers put 10 overweight and obese, sedentary, post-menopausal women on a diet that they call ‘paleolithic type’ and measured changes to several metabolic and anthropometric measures. The main areas they were looking for changes were fat deposits in the liver and skeletal muscles, and insulin sensitivity, but they measured several other things as well, including:

-waist circumference and waist-hip ratio
-blood pressure
-blood glucose

The diet:

“All meals were prepared by the food service at Ume University Hospital and were weighed and frozen after preparation. The diet included lean meat, fish, fruit, vegetables (including root vegetables), eggs and nuts. Dairy products, cereals, beans, legumes, refined fats and sugar, added salt, bakery products and soft drinks were excluded. Participants were instructed to complement the provided food with other included food items from the list, ad libitum. To enable preparation of additional complete meals at home, the women received 14-day menus together with recipes and instructions regarding portion sizes. They were also advised to
use only rapeseed (canola) or olive oil in food preparation.”

The diet worked out to roughly 30% protein, 40% fat (predominantly PUFA as saturated fat was limited in this study by design, and most of the fat the subjects consumed came from nuts, fish and canola and olive oils. Wait, canola oil? DO YOU EVEN PALEO?). They ate to appetite and documented their intake.

The results were quite good. The subjects lost an average of 10 pounds, blood pressure improved, both waist circumference and waist-hip ratio decreased, and heart rate decreased! And there was indeed a reduction in liver fat! Good stuff! Lets look a little deeper at that. From the study:

“The dietary regimen resulted in a significantly reduced energy intake (520 kcal/day reduction) despite the ad libitum approach. This may be one of the factors contributing to the striking decrease in liver fat content. A series of studies have indeed shown that hypocaloric diets reduce the amount of liver fat.”

Layman’s terms: the subjects spontaneously ate about 500 calories less per day than they had been eating before the study (I talk about why diets high in protein and fiber, like the one in this study, can lead to a spontaneous reduction in caloric intake here. Protein and fiber are satiating and highly thermic foods. Diets rich in protein and fiber, paleo or otherwise, are very good at producing a spontaneous caloric deficit. It’s not magic, it’s science). It’s been established that hypocaloric diets (hypocaloric = fewer calories consumed than burned) reduce liver fat. Rut roh. Are they saying it might have been the calorie reduction that decreased liver fat, not the magic of paleo? Why yes, yes I think they are.

Speaking of which, you know what else a caloric reduction decreases? Weight. Could it be that the subjects lost weight because they were eating fewer calories? That’s certainly where my money is. The study authors note that the weight loss seems out of proportion to the degree of calorie reduction but then go on to acknowledge:

“Possible explanations include over-reporting of energy intake, increased thermogenic effects of protein (versus other macronutrients) and loss of glycogen which may contribute to loss of body water during the study period. Of note, increased
urinary volumes were commonly reported among participants during this intervention.”

Layman’s terms: maybe the subjects were overreporting their food intake. Maybe there’s something to the Thermic Effect of Food dealio (if you didn’t read my post that I linked above on food thermogenesis, you can do it now). Or maybe, just maybe, the low-carb diet they were on did what low-carb diets always do: flushed out several pounds of water weight as the body’s glycogen stores depleted. The subjects did report peeing more, after all.

So, we looked at the anthropometric changes the diet produced, lets take a look at the metabolic changes. Some good news. Blood glucose and insulin both decreased, and total cholesterol, LDL and triglycerides decreased. HDL also decreased though (that’s the good cholesterol), and cortisol increased (cortisol is a stress hormone). So the metabolic measures were a mixed bag, but overall more good than bad. Not so fast though, glucose, insulin and cholesterol all respond favorably to weight loss, as does blood pressure. Could these improved markers be a response to the subjects’ weight loss, which was a response to reduced calorie intake? That conclusion is certainly supported by decades of credible science.

Back to the original aim of the study: to determine if a paleo diet reduces liver fat and increases insulin sensitivity. Liver fat did decrease, but it turns out that whole-body insulin sensitivity didn’t change, nor fat deposition in skeletal muscles:

“…lipid content in skeletal muscles, as determined by 1H-MRS, was unaltered, as was peripheral insulin sensitivity…”


“…exercise regimens must be included to demonstrate effects on muscle/whole-body insulin sensitivity…”

Layman’s terms: to improve insulin sensitivity you gotta move yo’ ass.

Bottom line: paleo is, as fad diets go, pretty decent. It encourages eating nutritious, whole foods, and accentuates protein and vegetables (staples of weight loss diets from the beginning of time). But it’s not magic. The positive outcomes experienced in this study fall right in line with decades of credible science showing similar outcomes from weight loss due to reduced caloric intake. I’m not hating on paleo: paleo is a healthy diet. But promoting the myth that eating paleo will magically reduce weight and improve metabolic markers is irresponsible for one very big reason: it won’t work for everyone, because not everyone will spontaneously eat fewer calories on a paleo diet. Some people will even eat MORE calories on paleo. And when those people don’t magically lose weight and get healthier, they may blame paleo. Or they may blame themselves. They may think they’re just not ‘paleo-ing’ hard enough. Let be honest: paleo is a healthy diet, and some people may lose weight and see health improvements on it because they spontaneously eat less. But it’s the eating less that is responsible for the weight loss, and if you’re NOT one of the people that spontaneously eats less on paleo, it’s not because paleo is bad, or because you’re doing it wrong, or because you’re destined to be fat or whatever else people have come up with to rationalize away undesired results. Paleo is a pretty decent way of eating but it’s not magic, it can’t rewrite the laws of physics.

Improving the quality of your diet is GREAT, and paleo can help some people do that. There are other ways of improving the quality of your diet, though, and there are other ways of optimizing your calorie intake. Lets sweep away the dogma and magical thinking and be realistic. This study shows what countless other studies have shown before it: that calories matter, that food quality ALSO matters, and that exercise is essential for healthy metabolic function. If paleo provides a framework that helps you succeed in those aras, that is fantastic! But it’s one possible helpful tool out of many, and what works for some doesn’t work for others, we must look critically at the causative factors here (calories, weight loss, exercise) if we want to create a balanced and effective path forward and help more people achieve better health.



22 thoughts on “Paleo Magic?

  1. Thank you for translating that article into normal speak for me. I started it and lost it in the first section. I tried Paleo, and it was not fun, now I eat the food, and my 80/20 refers to quality/it taste friggen delicious!!

  2. Any diet that has 30% energy from protein is testing another variable besides the Paleo hypothesis.
    With regard to liver fat, there have been trials of high-fat diets:
    “The findings show that 4 weeks of a very low carbohydrate diet reduces liver fat content and liver size, particularly of the left lobe.”
    “Six months of a low-carbohydrate, ketogenic diet led to significant weight loss and histologic improvement of fatty liver disease.”

    There is a mechanism whereby this would be expected to happen – carbohydrate restriction activates the PPAR-alpha transcription factor, this drives oxidation of fatty acids in the liver, carbohydrate suppresses PPAR-alpha.
    “There were no significant associations between either total caloric intake or protein intake and either steatosis, fibrosis, or inflammation. However, higher CHO intake was associated with significantly higher odds of inflammation, while higher fat intake was associated with significantly lower odds of inflammation. In conclusion, present dietary recommendations may worsen NAFLD histopathology.”

    Calorie restriction also activates PPAR-alpha, which may be the mechanism that prevented fatty liver in the mice in the famous Salk laboratory time-restricted feeding (IF) study.

    Exercise for NAFLD and NASH?
    Indeed this has been studied:
    “Neither moderate-intensity exercise nor total exercise per week was associated with NASH or stage of fibrosis. Meeting vigorous recommendations was associated with a decreased adjusted odds of having NASH (odds ratio (OR): 0.65 (0.43-0.98)). Doubling the recommended time spent in vigorous exercise, as is suggested for achieving additional health benefits, was associated with a decreased adjusted odds of advanced fibrosis (OR: 0.53 (0.29-0.97)).”

    Exercise significantly elevates PPAR-alpha in rats

    this gives us a range of strategies and combinations for fatty liver; paleo diets, carbohydrate restriction, ketogenic diets, calorie restriction, time-restricted feeding, and high-intensity exercise.

    • Excellent input as usual George. I’m looking forward to delving into your links when I get home this evening, thanks! :)

      • I have to credit you for drawing my attention to exercise as a PPAR-alpha agonist factor to add to my collection. PPAR-alpha is critical in hep C infection; the virus works to suppress it (leading to an increased rate of IR, DM2, metabolic inflexibilty in people with chronic hep C), while factors that activate PPAR-alpha inhibit viral replication (it likes to collect lipids and hates to see them burnt).
        I’m thinking that elevating hepatic PPAR-alpha is a better target than say lowering insulin or inflammation markers or whatever, because hepatic PPAR-alpha seems to be unambiguous. It doesn’t have a different role in a different context – it is always concerned with making fats combustible and suppressing their storage.

  3. Great breakdown of this study! Almost all diet studies that restrict calories (directly or indirectly) yield similar results (even the Twinkie diet!), but people tend to grab up the ones that support their theory of the “one-perfect-diet” as evidence that their way is the right way. Love that you sort the facts from the fiction.

    The loss of “extra” weight is likely water weight, as you mention, especially considering no added salt was allowed on the diet. Between that and low-carb, you’ve got a recipe for losing plenty of water!

  4. Paleo was disastrous for me, as I ate less, and I was already under eating! Calories matter :)

  5. I have read numerous, numerous studies on all sorts of low carb diet versions. Consistently the results of weight lost are from lowered total calorie intake.
    Chronically lowered caloric intake is not sustainable.

  6. While I think your analysis of the study was fairly decent (I’m an Epidemiologist), I think you’re a little misplaced in saying that there is nothing inherent in the Paleo diet that works- it’s just calorie restriction. First, as you touch on lightly, the Paleo diet naturally contributes to calorie restriction because you’re taking in high protein, high fiber, non-processed foods – you feel fuller, longer with less food – and that is a direct result of eating Paleo. As Americans typically overeat by an astonishing margin, this is a great boon of the Paleo diet and one of it’s main selling points. You can calorie restrict on a high carb diet as well, and you won’t see these benefits (in fact, high carb diets actually tend to increase cholesterol and a few other markers).

    And you’re right- it’s not magic. But I know of no one who follows the paleo diet who thinks it’s magic. It works for a couple reasons- 1. our bodies are not evolved to eat the sheer volume of grains and corn and other processed foods that most Americans shove into it. Empty calories are empty. Duh. (But seriously try getting away from corn products- they are literally in EVERYTHING). 2. Protein and fiber keeps you full naturally (see above). 3. Protein intake contributes to increased lean muscle mass development- which makes Paleo an excellent diet for athletes (which is why CrossFit heavily pushes it). 4. There are some pretty sound, scientific reasons for cutting out dairy and legumes. I won’t list them all here because that research is available. To be fair, I find this the hardest part (who doesn’t love ice cream ). 5. Paleo diets severely limit refined sugar intake, and substitute it for lower glycemic sugar options (raw honey mainly).

    Now anyone who follows the Paleo diet considers most of these things common sense – and they are (which is why when I use the term “diet” I literally mean “way of life”, not “something I do for a couple weeks to lose weight”). But here is what you left out of the discussion: mainstream medicine and nutrition do not subscribe to any of these common sense, evidenced-backed measures. Mainstream medicine and nutrition still emphasize low-fat diets (based on terribly faulty studies of cholesterol and fat), whole grains and carbohydrates (bottom of the food pyramid…really?), and counting calories for weight loss, among other things. That’s one of the reasons that Paleo is so huge to me- it’s trying to get back to an evolutionary correct, historically accurate diet for my body to function as well as it can. As cheesy as it sounds, I eat to live, not live to eat. And I can’t imagine not eating enough on the Paleo diet. I never count calories, I eat almost constantly, and am never hungry (and I work out over an hour a day). If you are hungry on Paleo, try a Paleo Zone approach – that’s a TON of food.

    It’s not easy, because crappy food tastes excellent (and finding real Paleo foods can be difficult). But it’s worth doing if you really want to be as healthy as possible.

    • You basically just reworded my post and presented it as evidence that I’m wrong. Huh?

      I’ve had PLENTY of clients who both underate and overate on paleo. Glad it works for you. Doesn’t work for everyone.

      • Where in your post do you point out that Paleo IS responsible for the benefits seen in the article? You spend most of your post refuting that and claiming its just because of fewer calories. And also, where do you talk about low-fat, low calorie diets (usually high in carbs) that don’t see the same benefits?

        I didn’t see one mention of evolution of our bodies, or anything on dairy or legumes and the research and scientific reasons why they aren’t terribly healthy.

        Nor did you point out that modern nutrition (and your diet) preach almost the exact opposite of the Paleo diet…much to people’s detriment.

        So how exactly did I reword what you said?

        There is no valid scientific reason why the Paleo diet “doesn’t work for everyone” or wouldn’t work for every human being – there are plenty of “I just couldn’t hack it” and “It was too hard to do” reasons for why it doesn’t work for everyone, but wasn’t that the point of your personal responsibility in nutrition post a little while back?

          • I have no idea. Did Amber even try Paleo? In an earlier post, she wrote that she tried fad diets…Paleo isn’t intended as a fad diet so if you stop eating clean, you most likely will gain weight.

            In another vein, I’d be curious about Amber’s internal health on the diet she is on now. Clearly, her external looks fabulous, but that’s not necessarily a reflection if internal health. Not saying this is the case for her- I’m just curious. The work up I have in mind, however, is rarely performed just because.

        • There’s no valid scientific reason that paleo DOES work for everyone either, there’s only dogma and anecdotes. There’s not even a standard definition of ‘paleo’, and every paleo guru’s paleo is slightly different. What there IS evidence of is that reducing intake of processed and refined foods is generally beneficial across the board (except perhaps in the case of extreme malabsorption issues in which case easy-to-digest simple carbs can be helpful to keep weight on a person while their gut heals). That’s why one of the few dietary recommendations I give is to eat more whole foods.

          Speaking of which, ‘my diet’ doesn’t ‘preach’ anything. Mostly because I don’t have ‘a diet’, but also because I don’t tell people what to eat.

          I didn’t get into the ‘scientific evidence’ that dairy and legumes ‘aren’t terribly healthy’ because I don’t find the scientific evidence of such terribly compelling. It’s scant, and outlying, and frequently taken out of context. I’m loathe to give dietary advice in the first place but I certainly wouldn’t give it based on science I don’t find credible. My dietary recommendations consist of: eat enough calories to support your activity (no starving yourself), get plenty of protein, and eat mostly whole foods. Beyond that I’ve read enough actual, credible science to know that every person is unique and has unique needs, challenges and goals, and there is no one diet that is right for every person.

          As for the nonsense about low fat diets, I have no idea where you are getting it. I don’t advocate that people restrict fat, and no medical professional I’ve ever worked with has advocated restricting fat. Why would I talk about low fat diets when they’re completely irrelevant to the subject at hand?

          • Yes, you must be right. All the research that I, and my other science colleagues do on the subject, is probably not convincing to the vast majority of lay people. Personally, I’m not trying to sell anything (including my time or expertise) so I can understand why you wouldn’t bother considering what I am saying. I won’t waste any time providing you the science as I’m sure you’ve seen it and deemed it “not convincing”. Best of luck in your journey and with your clients.

    • Allison

      “You can calorie restrict on a high carb diet as well, and you won't see these benefits (in fact, high carb diets actually tend to increase cholesterol and a few other markers).”

      Actually this is not true. A 2012 meta-analysis found low fat diets are better at reducing total cholesterol and LDL. Low carb diets are more effective at increasing HDL, decreasing triglycerides. But neither diet was more effective at reducing weight, waist girth, blood pressure, glucose & insulin levels.

      The authors concluded: ‘These findings suggest that low-carbohydrate diets are at least as effective as low-fat diets at reducing weight and improving metabolic risk factors.’

      “But I know of no one who follows the paleo diet who thinks it's magic.”

      You must not have been around the Paleo movement for long then or browse Facebook or paleo blogs to see that magical thinking is common. To be fair, it’s common in most dieters, but it is part of many paleo dieters’ claims. i.e. lost weight without even trying, you can eat what you want and you wont gain weight, etc. Many people are religiously zealous and in fact, consider the diet to be magic.

      “Protein intake contributes to increased lean muscle mass development- which makes Paleo an excellent diet for athletes (which is why CrossFit heavily pushes it)”

      Except most athletes are not low carb for obvious reasons.

      “… it's trying to get back to an evolutionary correct, historically accurate diet for my body to function as well as it can.”

      This idea seems appealing, but it doesn’t make as much sense as we wish. Which part of the paleolithic period are you referring to? In what region? Wouldn’t you be hunting wild big game and cooking it with no spices and picking random fruits (which is seasonal) to be ‘accurate’ or eating insects as well? What specifics or research can you offer for ‘historically accurate’ accounts of paleo diets?

      There are a wide variety of diet preferences that work for many different people – one lesson we get from human evolution is adaptation and variability – we are unique and can thrive on a variety of diets. To say one particular diet works for all people to get as healthy as possible is not accurate and indicative of magic thinking.

      Also, if you avoid dairy & sugar, you’re not going to have much fun…just sayin.

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