Charles Robert Darwin taught us that the life forms that make up the ecosystem of the Earth evolve via natural selection. Over evolutionary time, different organisms have adapted to different types of environmental conditions, including different types of diets. Natural selection is constantly at work, modifying the gene pool of the living world. These facts form the foundation upon which the evolutionary nutrition concept emerged, and guide Darwinian nutritionists and physicians in their quest for knowledge and wisdom
Up until quite recently, evolutionarily speaking, all humans on this planet ate a hunter-gatherer diet composed of wild plants and animal foods. We all carry the genetic legacy of this evolutionary past inside of us. The fact that we’re not that different from our hunter-gatherer forebears, genetically speaking, would lead one to predict that contemporary humans do very well on a diet that bears resemblance to the diet of the Paleolithic man.
It could be argued that Darwinian science, by itself, proves that the Paleo diet concept is valid. Not everyone is knowledgeable about Darwinian theory though. Most nutritionists and nutritional scientists, including many of those who design dietary guidelines for the public, have never been systematically exposed to evolutionary science. Furthermore, it would perhaps be a little reckless to just assume that the modern man should “eat like a hunter-gatherer”, without first putting hunter-gatherer type diets to the test in clinical trials.
The hypothesis that the Paleolithic diet matches well with the biology of the modern man – a hypothesis that was generated from evolutionary science – has now been tested in dozens of research studies. In today’s article, I thought I’d have a quick look at 10 of these studies. Keep in mind that pretty much all of the studies in this area indicate that Paleolithic-style diets are very healthful. In other words, I’m not specifically selecting studies in which the Paleolithic shines for this article, while deliberately leaving studies in which it doesn’t shine out. I’m only aware of one study in which the Paleolithic diet didn’t do that well, but that study has so many flaws that I don’t feel it deserves a spot on today’s list.
Before we jump in with the studies, I think it’s important to point out that not everyone does well on a Paleolithic-type diet. It’s important to recognize that we – contemporary humans – don’t live under Paleolithic conditions. That doesn’t mean that we can’t learn anything from hunter-gatherers about diet and health (we definitely can); however, it does suggest that there are certain considerations we have to make when we bring Paleolithic nutrition principles into the modern arena. Perhaps most importantly, it’s important to recognize that the physical activity pattern of some contemporary humans (e.g., athletes) differs markedly from that of hunter-gatherers, and that sick people have different nutritional requirements than healthy folks.
With that said, let’s move on to the studies…
1. Marked Improvement in Carbohydrate and Lipid Metabolism in Diabetic Australian Aborigines After Temporary Reversion to Traditional Lifestyle
Summary: The rationale for the present study was that temporarily reversing the urbanization process in diabetic Aborigines should improve all aspects of their carbohydrate and lipid metabolism that are linked to insulin resistance. Ten full-blood, diabetic Aborigines from the Mowanjum Community (Derby, Western Australia) agreed to be tested before and after living for 7 wk as hunter-gatherers in their traditional country in northwestern Australia. They were middle aged (53.9 ±1.8 yr) and overweight (81.9 ± 3.4 kg), and all lost weight steadily over the 7-wk period (average, 8 kg). A detailed analysis of food intake over 2 wk revealed a low-energy intake (1200 kcal/person/day). Despite the high contribution of animal food to the total energy intake (64%), the diet was low in total fat (13%) due to the very low fat content of wild animals.
Oral glucose tolerance tests (75 g glucose) were conducted in the urban setting and repeated at the end of 7 wk of traditional lifestyle. The marked improvement in glucose was due to both a fall in fasting glucose (11.6 ± 1.2 mM before, 6.6 ± 0.8 mM after) and an improvement in postprandial glucose clearance (incremental area under the glucose curve: 15.0 ±1.2 mmol/ L/h before, 11.7 ± 1.2 mmol/L/h after). Fasting plasma insulin concentration fell (23 ± 2 mU/L before, 12 ± 1 mU/L after) and the insulin response to glucose improved (incremental area under the insulin curve: 61 ± 18 mU/L/h before, 104 ± 21 mU/L/h after). The marked fall in fasting plasma triglycerides (4.0 ± 0.5 mM before, 1.2 ± 0.1 mM after) was due largely to the fall in VLDL triglyceride concentration (2.31 ± 0.31 mM before, 0.20 ± 0.03 mM after).
In conclusion, the major metabolic abnormalities of type II diabetes were either greatly improved or completely normalized in this group of Aborigines by relatively short reversal of the urbanization process. At least three factors known to improve insulin sensitivity (weight loss, low-fat diet, and increased physical activity) were operating in this study and would have contributed to the metabolic changes observed.
My comment: This is one of the most interesting studies on hunter-gatherer nutrition that has ever been published. It’s an old classic that ages very well. It’s arguably more relevant today than it was when it was published three decades ago. The experiment conducted by the researchers is a simple one. Ten diabetic, westernized Australian aborigines agreed to temporarily revert back to a traditional, hunter-gatherer diet and lifestyle for 7 weeks. Before and after the experiment, various tests were performed in order to elucidate how the intervention affected the participants’ health, including their weight and triglyceride and insulin levels.
Over the 7 weeks, the participants lost on average 8 kilograms. Moreover, their metabolic health improved dramatically. Other factors besides diet probably mediated some of these effects; however, I don’t think any reasonable person will disagree with me when I say that nutrition played a central role in this experiment. This study gave the Evolutionary Health Concept (EHC) an opportunity to rise to the occasion and prove itself. The EHC ceased that opportunity and displayed some pretty potent powers.
2. A Paleolithic Diet with and without Combined Aerobic and Resistance Exercise Increases Functional Brain Responses and Hippocampal Volume in Subjects with Type 2 Diabetes
Abstract: Type 2 diabetes is associated with impaired episodic memory functions and increased risk of different dementing disorders. Diet and exercise may potentially reverse these impairments. In this study, sedentary individuals with type 2 diabetes treated by lifestyle ± metformin were randomized to a Paleolithic diet (PD, n = 12) with and without high intensity exercise (PDEX, n = 12) for 12 weeks. Episodic memory function, associated functional brain responses and hippocampal gray matter volume was measured by magnetic resonance imaging. A matched, but not randomized, non-interventional group was included as a reference (n = 6). The PD included a high intake of unsaturated fatty acids and protein, and excluded the intake of dairy products, grains, refined sugar and salt. The exercise intervention consisted of 180 min of supervised aerobic and resistance exercise per week. Both interventions induced a significant weight loss, improved insulin sensitivity and increased peak oxygen uptake without any significant group differences. Furthermore, both interventions were associated with increased functional brain responses within the right anterior hippocampus, right inferior occipital gyrus and increased volume of the right posterior hippocampus. There were no changes in memory performance. We conclude that life-style modification may improve neuronal plasticity in brain areas linked to cognitive function in type 2 diabetes. Putative long-term effects on cognitive functions including decreased risk of dementing disorders await further studies.
My comment: This study was published very recently. Its unique in that it has some unorthodox endpoints. Instead of focusing primarily on something like weight loss, insulin sensitivity, or cardiovascular health – all recurring themes in nutritional research – the researchers who conducted this experiment were primarily interested in determining how the consumption of a Paleolithic-type diet affects episodic memory performance, hippocampal volume, and functional brain responses. It’s an interesting study.
3. A Paleolithic diet improves glucose tolerance more than a Mediterranean-like diet in individuals with ischaemic heart disease
Abstract:
AIMS/HYPOTHESIS: Most studies of diet in glucose intolerance and type 2 diabetes have focused on intakes of fat, carbohydrate, fibre, fruits and vegetables. Instead, we aimed to compare diets that were available during human evolution with more recently introduced ones.METHODS: Twenty-nine patients with ischaemic heart disease plus either glucose intolerance or type 2 diabetes were randomised to receive (1) a Palaeolithic (‘Old Stone Age’) diet (n = 14), based on lean meat, fish, fruits, vegetables, root vegetables, eggs and nuts; or (2) a Consensus (Mediterranean-like) diet (n = 15), based on whole grains, low-fat dairy products, vegetables, fruits, fish, oils and margarines. Primary outcome variables were changes in weight, waist circumference and plasma glucose AUC (AUC Glucose(0-120)) and plasma insulin AUC (AUC Insulin(0-120)) in OGTTs.RESULTS: Over 12 weeks, there was a 26% decrease of AUC Glucose(0-120) (p = 0.0001) in the Palaeolithic group and a 7% decrease (p = 0.08) in the Consensus group. The larger (p = 0.001) improvement in the Palaeolithic group was independent (p = 0.0008) of change in waist circumference (-5.6 cm in the Palaeolithic group, -2.9 cm in the Consensus group; p = 0.03). In the study population as a whole, there was no relationship between change in AUC Glucose(0-120) and changes in weight (r = -0.06, p = 0.9) or waist circumference (r = 0.01, p = 1.0). There was a tendency for a larger decrease of AUC Insulin(0-120) in the Palaeolithic group, but because of the strong association between change in AUC Insulin(0-120) and change in waist circumference (r = 0.64, p = 0.0003), this did not remain after multivariate analysis.
CONCLUSIONS/INTERPRETATION: A Palaeolithic diet may improve glucose tolerance independently of decreased waist circumference.
My comment: Is the Mediterranean diet a healthy diet? What about the Atkins diet, the South Beach Diet, and the Maasai diet? Are those healthy diets? In order to answer these questions, we first need to define what we mean by the word healthy. A typical westerner who eats a highly processed diet could probably adopt any of those diets and experience some pretty impressive health improvements if he managed to stick with his new nutritional regimen. Does that mean that all of the above diets are healthy? No… I wouldn’t say so. That’s too loose of a definition of healthy.
In order to elucidate how healthy – or unhealthy – a specific diet really is, one arguably has to test that diet against other diets. It’s not enough to simply instruct a group of people to eat the diet in question for a set period of time and perform various tests on them during the intervention in order to see how the diet affects them. Such an intervention wouldn’t really tell us that much about how healthy (or unhealthy) the diet actually is, seeing as we have no reference point to compare it against.
This is something great researchers recognize. It’s also the primary reason why many studies on Paleolithic nutrition have pitted the Paleolithic diet against other prudent diets. It’s very good that we have these studies, as they help us determine how healthful the Paleolithic diet is compared to other diets.
In the above study, the Paleolithic diet was pitted against a Mediterranean-like diet. The trial is a valuable component of the evolutionary nutrition literature, in large part because the Mediterranean diet is generally believed to be a very healthy diet.
4. Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study.
Abstract:
BACKGROUND: Our aim was to compare the effects of a Paleolithic (‘Old Stone Age’) diet and a diabetes diet as generally recommended on risk factors for cardiovascular disease in patients with type 2 diabetes not treated with insulin.METHODS: In a randomized cross-over study, 13 patients with type 2 diabetes, 3 women and 10 men, were instructed to eat a Paleolithic diet based on lean meat, fish, fruits, vegetables, root vegetables, eggs and nuts; and a Diabetes diet designed in accordance with dietary guidelines during two consecutive 3-month periods. Outcome variables included changes in weight, waist circumference, serum lipids, C-reactive protein, blood pressure, glycated haemoglobin (HbA1c), and areas under the curve for plasma glucose and plasma insulin in the 75 g oral glucose tolerance test. Dietary intake was evaluated by use of 4-day weighed food records.
RESULTS: Study participants had on average a diabetes duration of 9 years, a mean HbA1c of 6,6% units by Mono-S standard and were usually treated with metformin alone (3 subjects) or metformin in combination with a sulfonylurea (3 subjects) or a thiazolidinedione (3 subjects). Mean average dose of metformin was 1031 mg per day. Compared to the diabetes diet, the Paleolithic diet resulted in lower mean values of HbA1c (-0.4% units, p = 0.01), triacylglycerol (-0.4 mmol/L, p = 0.003), diastolic blood pressure (-4 mmHg, p = 0.03), weight (-3 kg, p = 0.01), BMI (-1 kg/m2, p = 0.04) and waist circumference (-4 cm, p = 0.02), and higher mean values of high density lipoprotein cholesterol (+0.08 mmol/L, p = 0.03). The Paleolithic diet was mainly lower in cereals and dairy products, and higher in fruits, vegetables, meat and eggs, as compared with the Diabetes diet. Further, the Paleolithic diet was lower in total energy, energy density, carbohydrate, dietary glycemic load, saturated fatty acids and calcium, and higher in unsaturated fatty acids, dietary cholesterol and several vitamins. Dietary GI was slightly lower in the Paleolithic diet (GI = 50) than in the Diabetic diet (GI = 55).
CONCLUSION: Over a 3-month study period, a Paleolithic diet improved glycemic control and several cardiovascular risk factors compared to a Diabetes diet in patients with type 2 diabetes.
My comment: This is another study that was conducted with the purpose of testing how healthy the Paleolithic diet is compared to other diets. This time, the opponent that the Paleolithic diet faced wasn’t the Mediterranean diet, but rather a Diabetes diet. A diet that is specifically designed to treat diabetes must surely be a truly great diet for people with diabetes, right? Not necessarily. This study, at least, indicate that another diet, namely the Paleolithic diet, is an even healthier option for individuals with type-2 diabetes.
5. Effects of a Paleolithic diet with and without supervised exercise on fat mass, insulin sensitivity, and glycemic control: a randomized controlled trial in individuals with type 2 diabetes
Abstract:
Background: Means to reduce future risk for cardiovascular disease in subjects with type 2 diabetes are urgently needed.
Methods: Thirty-two patients with type 2 diabetes (age 59±8 years) followed a Paleolithic diet for 12 weeks. Participants were randomized to either standard care exercise recommendations (PD) or 1-h supervised exercise sessions (aerobic exercise and resistance training) three times per week (PD-EX).
Results: For the within group analyses, fat mass decreased by 5.7 kg (IQR: −6.6, −4.1; p<0.001) in the PD group and by 6.7 kg (−8.2, −5.3; p<0.001) in the PD-EX group. Insulin sensitivity (HOMA-IR) improved by 45% in the PD (p<0.001) and PD-EX (p<0.001) groups. HbA1c decreased by 0.9% (−1.2, −0.6; p<0.001) in the PD group and 1.1% (−1.7, −0.7; p<0.01) in the PD-EX group. Leptin decreased by 62 % (p<0.001) in the PD group and 42 % (p<0.001) in the PD-EX group. Maximum oxygen uptake increased by 0.2 L/min (0.0, 0.3) in the PD-EX group, and remained unchanged in the PD group (p<0.01 for the difference between intervention groups). Male participants decreased lean mass by 2.6 kg (−3.6, −1.3) in the PD group and by 1.2 kg (−1.3, 1.0) in the PD-EX group (p<0.05 for the difference between intervention groups).
Conclusions: A Paleolithic diet improves fat mass and metabolic balance including insulin sensitivity, glycemic control, and leptin in subjects with type 2 diabetes. Supervised exercise training may not enhance the effects on these outcomes, but preserves lean mass in men and increases cardiovascular fitness.
My comment: Regular exercise is an essential component of a healthy lifestyle. No doubt about that. But how much of an added benefit do you get from exercising in addition to eating healthy? That’s an interesting question. I’m not the only one who thinks so. Other health conscious people appear to do as well, including the researchers who’ve used that question as the basis for creating and conducting scientific experiments.
We’ve already talked about one such experiment, namely the study mentioned under point 2 on this list. That study is somewhat similar to the one that’s now in focus. It’s not identical though. What’s particularly interesting about the study that’s now in focus is that it found that the addition of supervised exercise to a Paleolithic diet regimen did not cause a significant additional reduction in fat mass or improvements related to metabolic health. It conferred increased preservation of lean mass in men and improved cardiovascular fitness though.
This doesn’t mean that it’s a waste of time for people who want to lose weight and improve their metabolic health to exercise. It definitely isn’t. However, the study does highlight one thing, and that is that our body composition, insulin sensitivity, leptin levels, and blood glucose levels are largely determined by what we eat.
6. Metabolic and physiologic effects from consuming a hunter-gatherer (Paleolithic)-type diet in type 2 diabetes.
Abstract:
BACKGROUND/OBJECTIVES:: The contemporary American diet figures centrally in the pathogenesis of numerous chronic diseases–‘diseases of civilization’–such as obesity and diabetes. We investigated in type 2 diabetes whether a diet similar to that consumed by our pre-agricultural hunter-gatherer ancestors (‘Paleolithic’ type diet) confers health benefits.SUBJECTS/METHODS: We performed an outpatient, metabolically controlled diet study in type 2 diabetes patients. We compared the findings in 14 participants consuming a Paleo diet comprising lean meat, fruits, vegetables and nuts, and excluding added salt, and non-Paleolithic-type foods comprising cereal grains, dairy or legumes, with 10 participants on a diet based on recommendations by the American Diabetes Association (ADA) containing moderate salt intake, low-fat dairy, whole grains and legumes. There were three ramp-up diets for 7 days, then 14 days of the test diet. Outcomes included the following: mean arterial blood pressure; 24-h urine electrolytes; hemoglobin A1c and fructosamine levels; insulin resistance by euglycemic hyperinsulinemic clamp and lipid levels.
RESULTS: Both groups had improvements in metabolic measures, but the Paleo diet group had greater benefits on glucose control and lipid profiles. Also, on the Paleo diet, the most insulin-resistant subjects had a significant improvement in insulin sensitivity (r = 0.40, P = 0.02), but no such effect was seen in the most insulin-resistant subjects on the ADA diet (r = 0.39, P = 0.3).
CONCLUSIONS: Even short-term consumption of a Paleolithic-type diet improved glucose control and lipid profiles in people with type 2 diabetes compared with a conventional diet containing moderate salt intake, low-fat dairy, whole grains and legumes.
My comment: The results of this study are in line with those of the aforementioned study entitled Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study. Both of the studies indicate that the Paleolithic diet is more therapeutic for type-2 diabetes sufferers than a stereotypical diabetes diet. The study that’s now in focus had few participants and a short intervention period; however, its results are interesting nonetheless.
7. Paleolithic nutrition improves plasma lipid concentrations of hypercholesterolemic adults to a greater extent than traditional heart-healthy dietary recommendations.
Abstract: Recent research suggests that traditional grain-based heart-healthy diet recommendations, which replace dietary saturated fat with carbohydrate and reduce total fat intake, may result in unfavorable plasma lipid ratios, with reduced high-density lipoprotein (HDL) and an elevation of low-density lipoprotein (LDL) and triacylglycerols (TG). The current study tested the hypothesis that a grain-free Paleolithic diet would induce weight loss and improve plasma total cholesterol, HDL, LDL, and TG concentrations in nondiabetic adults with hyperlipidemia to a greater extent than a grain-based heart-healthy diet, based on the recommendations of the American Heart Association. Twenty volunteers (10 male and 10 female) aged 40 to 62 years were selected based on diagnosis of hypercholesterolemia. Volunteers were not taking any cholesterol-lowering medications and adhered to a traditional heart-healthy diet for 4 months, followed by a Paleolithic diet for 4 months. Regression analysis was used to determine whether change in body weight contributed to observed changes in plasma lipid concentrations. Differences in dietary intakes and plasma lipid measures were assessed using repeated-measures analysis of variance. Four months of Paleolithic nutrition significantly lowered (P < .001) mean total cholesterol, LDL, and TG and increased (P < .001) HDL, independent of changes in body weight, relative to both baseline and the traditional heart-healthy diet. Paleolithic nutrition offers promising potential for nutritional management of hyperlipidemia in adults whose lipid profiles have not improved after following more traditional heart-healthy dietary recommendations.
My comment: Hypercholesterolemia is today an extremely common condition, particularly in westernized nations. When compared to hunter-gatherers, industrialized people have very high cholesterol levels. It’s particularly concerning that many contemporary humans have high levels of LDL cholesterol circulating in their bodies, seeing as high LDL levels is a well-established risk factor for cardiovascular disease.
Given that hypercholesterolemia is such a common disorder nowadays and that the food we eat has a significant impact on our cholesterol levels, it’s not surprising that nutritional scientists devote a lot of attention to figuring out what the best dietary strategy for improving a less-than-ideal blood lipid profile is. The above study adds to the evidence indicating that Paleolithic-style diets trump diets based on traditional heart-healthy dietary recommendations with respects to their impact on blood lipid levels.
8. Long-term effects of a Palaeolithic-type diet in obese postmenopausal women: a 2-year randomized trial.
BACKGROUND/OBJECTIVES: Short-term studies have suggested beneficial effects of a Palaeolithic-type diet (PD) on body weight and metabolic balance. We now report the long-term effects of a PD on anthropometric measurements and metabolic balance in obese postmenopausal women, in comparison with a diet according to the Nordic Nutrition Recommendations (NNR).
SUBJECTS/METHODS: Seventy obese postmenopausal women (mean age 60 years, body mass index 33 kg/m(2)) were assigned to an ad libitum PD or NNR diet in a 2-year randomized controlled trial. The primary outcome was change in fat mass as measured by dual-energy X-ray absorptiometry.
RESULTS: Both groups significantly decreased total fat mass at 6 months (-6.5 and-2.6 kg) and 24 months (-4.6 and-2.9 kg), with a more pronounced fat loss in the PD group at 6 months (P<0.001) but not at 24 months (P=0.095). Waist circumference and sagittal diameter also decreased in both the groups, with a more pronounced decrease in the PD group at 6 months (-11.1 vs-5.8 cm, P=0.001 and-3.7 vs-2.0 cm, P<0.001, respectively). Triglyceride levels decreased significantly more at 6 and 24 months in the PD group than in the NNR group (P<0.001 and P=0.004). Nitrogen excretion did not differ between the groups.
CONCLUSIONS: A PD has greater beneficial effects vs an NNR diet regarding fat mass, abdominal obesity and triglyceride levels in obese postmenopausal women; effects not sustained for anthropometric measurements at 24 months. Adherence to protein intake was poor in the PD group. The long-term consequences of these changes remain to be studied.
My comment: The participants of this study followed their assigned diet for as long as 2 years. There are both upsides and downsides to having such a long intervention period. The most obvious upside is that having a lengthy intervention period allows one to assess what the long-term impacts of the relevant exposures are. It takes time to lose weight and improve one’s general health. Moreover, many health conditions take months or years to develop and treat; hence, it makes sense to have a long intervention period in diet studies.
There are several downsides to having a long intervention period though. Among other things, it’s time-consuming and often expensive to perform lengthy studies. Moreover, compliance is often poor in nutritional studies that go over many years, because a lot of people find it difficult to adhere to a specific diet or nutritional regimen for a long period of time, particularly if they have to adhere to fairly rigid instructions. This could help explain why the above study found that the Paleolithic diet group had “outperformed” the group that ate a diet based on the Nordic Nutrition Recommendations (NNR) at 6 months with respects to anthropometric measurements, but not at 24 months.
This study is a very interesting one. Not just because it lasted for as long as two years and included as many as 70 participants, but also because the Paleolithic diet was pitted against a diet that is by many believed to be very healthful.
9. The kitava study
Abstract:
OBJECTIVES: To compare cardiovascular risk factor levels between non-westernized Melanesians, apparently free from stroke and ischaemic heart disease, nd healthy Swedish populations, and to analyse, among adult Melanesians, relations with age, sex and smoking status.
DESIGN: Cross-sectional survey.
SUBJECTS: (i) Traditional horticulturalists in Kitava, Trobriand Islands, Papua New Guinea, uninfluenced by western diet. this study tested 151 males and 69 females aged 14-87 years with 76% and 80% smokers over 20 years. (ii) Healthy Swedish reference populations.
MAIN OUTCOME MEASURES: Sitting systolic and diastolic blood pressure, weight, height, body mass index, circumferences of waist, pelvis and mid upper arm, triceps skinfold thickness, fasting serum total cholesterol, triglycerides, high-density lipoprotein cholesterol, estimated low-density lipoprotein cholesterol, apolipoprotein B, apolipoprotein A1 and apolipoprotein (a).
RESULTS: Compared to Sweden, diastolic blood pressure, body mass index and triceps skinfold thickness were substantially lower in Kitava, where all subjects > or = 40 years were below Swedish medians. Among males > or = 20 and females > or = 60 years systolic blood pressure was lower in Kitavans. Fasting serum total cholesterol, low-density lipoprotein cholesterol and apolipoprotein B were 10-30% lower in Kitavan males > or = 40 and females > or = 60 years. Triglycerides were higher in Kitavans aged 20-39. High-density lipoprotein cholesterol did not differ while apolipoprotein A1 was lower in Kitavans. Apolipoprotein (a) tended to be lower in Kitavans, but the differences were small.
CONCLUSIONS: Of the analysed variables, leanness and low diastolic blood pressure seem to offer the best explanations for the apparent absence of stroke and ischaemic heart disease in Kitava. The lower serum cholesterol may provide some additional benefit. Differences in dietary habits may explain the findings.
My comments: I’ve talked quite a bit about the Kitava study, which was conducted by Staffan Lindeberg and colleagues, here on the site in the past, so I’m not going to repeat myself here. There are many possible explanations as to why the people Dr. Lindeberg found when he visited the Island of Kitava, a part of the Melanesian Islands, in 1989 were so healthy. Diet is only one of the many factors that have to be taken into account. That said, there’s no doubt in my mind that one of the primary reasons why the Kitavans are so healthy is that they consume a natural, whole foods diet.
The traditional diet of the Kitavans is not identical to the diet that our African Paleolithic forebears ate. Among other things, it’s higher it starch. It has some important things in common with the Paleolithic diet though, chief of which is that it’s devoid of highly processed foods, grains, and dairy products. This helps explain why Kitavans who adhere to a traditional diet and lifestyle are in such supreme health.
10. Decreased lipogenesis-promoting factors in adipose tissue in postmenopausal women with overweight on a Paleolithic-type diet.
PURPOSE: We studied effects of diet-induced postmenopausal weight loss on gene expression and activity of proteins involved in lipogenesis and lipolysis in adipose tissue.
METHODS: Fifty-eight postmenopausal women with overweight (BMI 32.5 ± 5.5) were randomized to eat an ad libitum Paleolithic-type diet (PD) aiming for a high intake of protein and unsaturated fatty acids or a prudent control diet (CD) for 24 months. Anthropometry, plasma adipokines, gene expression of proteins involved in fat metabolism in subcutaneous adipose tissue (SAT) and lipoprotein lipase (LPL) activity and mass in SAT were measured at baseline and after 6 months. LPL mass and activity were also measured after 24 months.
RESULTS: The PD led to improved insulin sensitivity (P < 0.01) and decreased circulating triglycerides (P < 0.001), lipogenesis-related factors, including LPL mRNA (P < 0.05), mass (P < 0.01), and activity (P < 0.001); as well as gene expressions of CD36 (P < 0.05), fatty acid synthase, FAS (P < 0.001) and diglyceride acyltransferase 2, DGAT2 (P < 0.001). The LPL activity (P < 0.05) and gene expression of DGAT2 (P < 0.05) and FAS (P < 0.05) were significantly lowered in the PD group versus the CD group at 6 months and the LPL activity (P < 0.05) remained significantly lowered in the PD group compared to the CD group at 24 months.
CONCLUSIONS: Compared to the CD, the PD led to a more pronounced reduction of lipogenesis-promoting factors in SAT among postmenopausal women with overweight. This could have mediated the favorable metabolic effects of the PD on triglyceride levels and insulin sensitivity.
My comment: This study, which was published quite recently, also lasted for 2 years, just like the trial mentioned prior to the Kitava study. It makes me happy to see that new studies on Paleolithic nutrition keep appearing in the scientific literature. In particular studies such as this one, which involve a long-term assessment of the therapeutic effects of Paleolithic-type diets, are very valuable and may perhaps help push the conventional nutrition community to recognize that there is something to this Paleo diet thing.
Picture: By Maarten van den Heuvel on Unsplash
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