|The good thing about paleo is that you can eat a broad range of foods. An advantage that makes paleo versatile and tasty enough to adhere to.|
Just to make sure there's no confusion. I am not saying that everything that Eaton, Cordain and others wrote is bogus. I am just saying that their papers are above everything else the material based on which others have formulated research hypothesis and done experimental research. Research that has been reviewed in a soon-to-be-published paper in the influential American Journal of Clinical Nutrition, by Eric W Manheimer, Esther J van Zuuren, Zbys Fedorowicz, and Hanno Pijl. A paper that leaves its readers with a generally positive conclusion, but state that "[t]he available data warrant additional evaluations of the health benefits of Paleolithic nutrition" (Manheimer. 2015). Now that does not sound like much, but in view of the scarcity of evidence it is more than you'd usually expect from a review that was partly financed by the National Center for Complementary and Alternative Medicine of the US.
When they decided on the methodology, inclusion and exclusion criteria, Manheimer et al. began with the simple, but important question "Does paleo-nutrition improve risk factors for chronic disease more than other dietary interventions in people with the metabolic syndrome?" To answer this question, the authors searched the following bibliographic databases for reports of controlled trials without any language restriction (likewise included were relevant results from the following ongoing trials databases):
Figure 1: Details of the selection process in January 2015 (Manheimer. 2015).
- MEDLINE via OVID (from 1946)
- EMBASE via OVID (from 1974)
- LILACS (Latin American and Caribbean Health Science Information database, from 1982)
- Science Citation Index (from 1988 to the present).
- The metaRegister of Controlled Trials
- The U.S. National Institutes of Health Ongoing Trials Register
- The Australian and New Zealand Clinical Trials Registry
- The World Health Organization International Clinical Trials Registry platform
"Randomised controlled trials will be included. Any other study design will be excluded. We will only include cross-over trials if we are able to extract the relevant data from the first phase (i.e., before the crossover occurred) because we consider the risk for carryover effects to be prohibitive" (Manheimer. 2015).In addition, the scientists looked for dietary interventions which were designed to emulate as much as possible, for the modern time, the diet of plants and animals eaten by human beings during the Paleolithic era. More precisely, Manheimer et al. included only studies with diets with...
- large amounts of vegetables (including root vegetables),
- fruits (including fruit oils e.g., olive oil, coconut oil, palm oil),
- nuts, fish, meat, and eggs
Important side note: I would like to use the chance to highlight that this diet - if it was not for the (imho) unnecessarily rigid exclusion of dairy and legumes - is actually very similar to what fitness experts have been suggesting for decades. If you do the math on the macros in Eaton's recommendation you end up with 32.5% protein, 22.8% fat, 43.7% carbohydrates and the rest of the energy in form of fiber. With this common macro ratio from the fitness community and the requirement to "get all of that from whole foods" you end up eating almost the same diet.
"In this systematic review and meta-analysis of 4 RCTs, Paleolithic nutrition resulted in greater short-term pooled improvements on each of the 5 components of the metabolic syndrome than did currently recommended guideline-based control diets. However, the greater pooled improvements did not reach significance for 2 of the 5 components (i.e., HDL cholesterol and fasting blood sugar). For each metabolic syndrome component, the quality of the evidence for the pooled estimate for improvement was moderate" (Manheimer. 2015).I guess what these results mean is much easier to grasp if you take a look at the plot of the data I've created for you. Keep in mind: What you see in Figure 1 are the differences compared to the allegedly "optimal" recommended diets in the respective studies, not differences to the habitual diets of the subjects which were probably significantly more pronounced.
|Figure 2: Improvements in triglycerides, HDL, fasting blood sugar, waist circumference, systolic and diastolic blood pressure with "paleo" diets vs. nationally recommended diets (Manheimer. 2015).|
Meat vs. beans - what's more satiating? A recent study from the University of Minnesota did a "paleo-relevant" comparison of the satiety effects of meat- and bean-based meals. More specifically, Bonnema and her colleagues compared the satiety response to a beef meal providing 26 g of protein and 3 g of fiber to a bean meal providing 17 g of protein and 12 g of fiber. What they found may surprise the non-paleo-lovers out there: "[The] beef-based meal with high protein and [the] bean-based meal with moderate protein and high fiber produced similar satiety, while the bean-based meal resulting in higher, yet moderate, gas and bloating" (Bonnema. 2015). Since both lead to a reduced energy intake on subsequent meals, both the anti-paleo legume-based and the paleo meat-based meal "could equate to weight loss and/or management over time" (ibid.).After all, more than 50 million people in the US alone are suffering from full-blown hypertension (high blood pressure). In view of the fact that even pre-hypertension is associated with an 80% increased risk of cardiovascular morbidity (learn more), the consumption of a paleo-esque diet could thus save the lives of millions of people. In view of the fact that this would also save us billions of dollars that are spent on managing hypertension every year, this is probably the strongest argument in favor of the "paleo diet" (Note: It's not an exclusive advantage, though. The DASH diet with a similar if not higher vegetable and fruit content has similar effects).
|Figure 3: Increase in all-cause mortality risk among 48 500 men and 56 343 women, 50 years or older, in the Cancer Prevention Study II Nutrition Cohort according to BMI and waist circumference (Jacobs. 2010).|
- Boers, Inge, et al. "Favourable effects of consuming a Palaeolithic-type diet on characteristics of the metabolic syndrome: a randomized controlled pilot-study." Lipids Health Dis 13.1 (2014): 160.
- Eaton, S. Bovn, M. Konner, and N. Paleolithic. "A consideration of its nature and current implications." N Engl j Med 312.5 (1985): 283-9.
- Jacobs, Eric J., et al. "Waist circumference and all-cause mortality in a large US cohort." Archives of internal medicine 170.15 (2010): 1293-1301.
- Jönsson, Tommy, et al. "Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study." Cardiovasc Diabetol 8.35 (2009): 1-14.
- Lindeberg, Staffan, et al. "A Palaeolithic diet improves glucose tolerance more than a Mediterranean-like diet in individuals with ischaemic heart disease." Diabetologia 50.9 (2007): 1795-1807.
- Manheimer, et al. "Paleolithic nutrition for metabolic syndrome: systematic review and meta-analysis." American Journal of Clinical Nutrition (2015): Ahead of print.
- Mellberg, Caroline, et al. "Long-term effects of a Palaeolithic-type diet in obese postmenopausal women: a 2-year randomized trial." European journal of clinical nutrition 68.3 (2014): 350-357.