Tag Archives: paleo diet

September 27, 2011 · 2:38 PM

Introducing Paleo Diabetic, a New Blog

A few of my patients have asked me if the paleo diet and lifestyle would be good for their diabetes.  I’m not sure.  A few pilot studies suggest it would be.  I expect much more published scientific research over the coming decade, in addition to self-experimentation reports by patients.  I’ll be looking into the matter at Paleo Diabetic.

The paleo diet in modern times began gathering steam in 2008.  It’s still not widely known or followed, but the trend is definitely upwards. 

The idea behind the paleo diet—also referred to as the Stone Age or caveman diet—is that optimal health depends on adherence to dietary and lifestyle factors to which we’re genetically adapted.  Our current mix of genes overwhelmingly reflects the Paleolithic era of human cultural development, starting anywhere from 750,000 to 2.5 million years ago, and ending around 10,000 years ago.  It’s also called the Stone Age.

The paleo diet pattern isn’t set in stone.  In general, it includes nuts, vegetables, fruits, fish, meat, and poultry.  It excludes or limits grains, dairy, legumes, sugars other than fruit or honey, industrial seed oils (e.g., from soybean and corn), and modern processed, highly refined foods.  Fresh, natural, and “organic” are preferred.

I’ve already got a few posts up and plan on new ones once or twice weekly.  If you’re interested, please join me at Paleo Diabetic.

Steve Parker, M.D.

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August 29, 2011 · 8:05 AM

How Common Is Celiac Disease?

Celiac disease, aka gluten enteropathy, affects one of every 133 Americans, according to the National Digestive Diseases Information Clearinghouse.  That’s much more common than we thought a couple decades ago.  Read about celiac disease symptoms and physical signs at About.com or the NDDIC link.

I read a few paleo diet/lifestyle blogs regularly.  In case you didn’t know, paleo diet advocates shun wheat and other grains.  Recent paleo converts often report how this or that symptom or physical condition improved when the dieter “went paleo,” often attributing the improvement to cutting out wheat products.   Wheat contains a protein—gluten—that causes disease in people who have celiac disease.  Other sources of gluten are barley and rye.

Visit WebMD for details about celiac disease: http://www.webmd.com/digestive-disorders/celiac-disease/default.htm

Click to see one definition of the paleo diet: http://paleodiet.com/definition.htm

An article in the Wall Street Journal implies that star tennis player Novak Djokovic’s recent winning streak is attributable to a gluten-free (and low-carb) diet.  Click for details: http://online.wsj.com/article/SB10001424052748703509104576327624238594818.html 

Here are Dr. Barbara Berkeley’s thoughts on Djokovic: http://refusetoregain.com/refusetoregain/2011/08/novak-djokovic-the-diet-that-conquered-tennis.html

Or is Djokovic playing so well because of the CVAC pod?: http://online.wsj.com/article/SB10001424053111904787404576532854267519860.html

If cutting out wheat from your diet improves or resolves bothersome medical symptoms, it makes me wonder if you have celiac disease.  Other possible explanations include placebo effect and coincidence.  And if you switch from a standard American diet to paleo, you’re doing more than just eliminating gluten.

I reviewed several sources for the prevalence of celiac disease in the U.S.  The best figure is one of every 133 residents. 

Most countries have a prevalence of roughly one of every 350 citizens.  Prevalence varies by country and ancestry; celiac disease is at least twice as common in whites of northern European lineage.

Full-blown classic celiac disease is relatively easy for doctors to recognize, but that’s only the tip of the iceberg.  Adults more commonly have one or two milder, nonspecific manifestations such as fatigue, malaise, depression, malnutrition (especially low iron, folate, or vitamin D), neuropathy, belly pain, headaches, thin bones, diarrhea, or a rash.  I’m glad to see increasing physician and public awareness of gluten intolerance.  If it’s not considered as a cause of these symptoms, it’ll never be diagnosed and treated appropriately.

Celiac disease is being diagnosed more often because of the availability of blood tests that help us screen for it.  If you think you have celiac disease, consider getting one of two blood tests: IgA antibodies to tissue transglutaminase, or IgA endomysial antibodies.  If that test is positive and symptoms or physical signs suggest celiac disease, the next step is usually a small bowel biopsy.

Steve Parker, M.D.

Update August 31, 2011: Tom Naughton reviewed Dr. William Davis’ new book, Wheat Belly, yesterday.  In the book, Dr. Davis notes that modern wheat varieties are vastly different from their ancient ancestors, different even than wheat of 50 years ago.  The modern varieties apparently contain much more of the gluten proteins that trigger immunologic celiac symptoms. 

Update September 13, 2011: A recent study of adult type 1 diabetics at a U.K. teaching hospital found celiac disease in three of every hundred cases.

References: WebMD.com (about one in a hundred US residents affected), University of Chicago Celiac Disease Center (one in 133 Americans affected), and MedicineNet.com (one in 3000 (sic) North Americans affected), UpToDate.com (in most countries, one in 350 have celiac disease), National Digestive Diseases Information Clearinghouse (one in 133 in U.S.).

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March 13, 2011 · 7:46 AM

Pilot Study: Paleo Diet Is More Satiating Than Mediterranean-Style

Swedish researchers reported recently that a Paleolithic diet was more satiating than a Mediterranean-style diet, when compared on a calorie-for-calorie basis in heart patients.  Both groups of study subjects reported equal degrees of satiety, but the paleo dieters ended up eating 24% fewer calories over the 12-week study.

The main differences in the diets were that the paleo dieters had much lower consumption of cereals (grains) and dairy products, and more fruit and nuts.  The paleos derived 40% of total calories from carbohydrate compared to 52% among the Mediterraneans.

Even though it wasn’t a weight-loss study, both groups lost weight.  The paleo dieters lost a bit more than the Mediterraneans: 5 kg vs 3.8 kg (11 lb vs 8.4 lb).  That’s fantastic weight loss for people not even trying.  Average starting weight of these 29 ischemic heart patients was 93 kg (205 lb).  Each intervention group had only 13 or 14 patients (I’ll let you figure out what happened to to the other two patients).

I blogged about this study population before.  Participants supposedly had diabetes or prediabetes, although certainly very mild cases (average hemoglobin A1c of 4.7% and none were taking diabetic drugs)

As I slogged through the research report, I had to keep reminding myself that this is a very small, pilot study.  So I’ll not bore you with all the details.

Bottom Line

This study suggests that the paleo diet may be particularly helpful for weight loss in heart patients.  No one knows how results would compare a year or two after starting the diet.  The typical weight-loss pattern is to start gaining the weight back at six months, with return to baseline at one or two years out.

Greek investigators found a link between the Mediterranean diet and better clinical outcomes in known ischemic heart disease patients.  On the other hand, researchers at the Heart Institute of Spokane found the Mediterranean diet equivalent to a low-fat diet in heart patients, again in terms of clinical outcomes.  U.S. investigators in 2007 found a positive link between the Mediterranean diet and lower rates of death from cardiovascular disease and cancer. 

We don’t yet have these kinds of studies looking at the potential benefits of the paleo diet.  I’m talking about hard clinical endpoints such as heart attacks, heart failure, cardiac deaths, and overall deaths.  The paleo diet definitely shows some promise.

I also note the Swedish investigators didn’t point out that weight loss in overweight heart patients may be detrimental.  This is the “obesity paradox,” called “reverse epidemiology” at Wikipedia.  That’s a whole ‘nother can o’ worms.

Keep your eye on the paleo diet.

Steve Parker, M.D.

Reference: Jonsson, Tommy, et al.  A paleolithic diet is more satiating per calorie than a mediterranean-like diet in individuals with ischemic heart disease.  Nutrition and Metabolism, 2010, 7:85.

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December 19, 2010 · 2:00 AM

Quote of the Day

Here’s one the paleo diet advocates will like.

The deviation of man from the state in which he was originally placed by nature seems to have proved to him a prolific source of diseases.

—Edward Jenner (1749-1823), of smallpox vaccination fame

Masai men in Tanzania. Modern hunter-gatherers?

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November 3, 2010 · 2:00 AM

Paleo and Low-Carb Diets: Much In Common?

My superficial reading of the paleo diet literature led me to think Dr. Loren Cordain was the modern originator of this trend, so I was surprised to find an article on the Stone Age diet and modern degenerative diseases in a 1988 American Journal of Medicine.  Dr. Cordain started writing about the paleo diet around 2000, I think.

What’s So Great About the Paleolithic Lifestyle?

In case you’re not familiar with paleo diet theory, here it is.  The modern human gene pool has changed little over the last 50,000 years or so, having been developed over the previous one or two million years.  Darwins’ concept of Natural Selection suggests that organisms tend to thrive if they adhere to conditions present during their evolutionary development.  In other words, an organism is adapted over time to thrive in certain environments, but not others.

The paleo diet as a healthy way to eat appeals to me.  It’s a lifestyle, really, including lots of physical activity, avoidance of toxins, adequate sleep, etc. 

The Agricultural Revolution (starting about 10,000 years ago) and the Industrial Revolution (onset a couple centuries ago) have produced an environment vastly different from that of our Paleolithic ancestors, different from what Homo sapiens were thriving in for hundreds of thousands of years.  That discordance leads to obesity, type 2 diabetes, atherosclerosis, high blood pressure, and some cancers.  Or so goes the theory.

What’s the Paleolithic Lifestyle? (according to the article)

  • Average life expectancy about half of what we see these days
  • No one universal subsistence diet
  • Food: wild game (lean meat) and uncultivated vegetables and fruits (no dairy or  grain)
  • Protein provided 34% of calories (compared to about 12 in U.S. in 1988)
  • Carbohydrate provided 46% of calories (only a  tad lower than what we eat today)
  • Fat provided 21% of calories (42% today)
  • Little alcohol, but perhaps some on special occasions (honey and wild fruits can undergo natural fermentation) , compared to 7-10% of calories in U.S. today [I didn’t know it was that high]
  • No tobacco
  • More polyunsaturated than saturated fats (we ate more saturated than polyunsaturated fat, at least in 1988)
  • Minimal simple sugar availability except when honey in season
  • Food generally was less calorically dense compared to modern refined, processed foods
  • 100-150 grams of dietary fiber daily, compared to 15-20 g today
  • Two or three times as much calcium as modern Americans
  • Under a gram of sodium daily, compared to our 3 to 7 grams.
  • Much more dietary potassium than we eat
  • High levels of physical fitness, with good strength and stamina characteristic of both sexes at all ages achieved through physical activity

[These points are all debatable, and we may have better data in 2010.]

The article authors point out that recent unacculturated native populations that move to a modern Western lifestyle (and diet) then see much higher rates of obesity, diabetes, atheroslcerosis, high blood pressure, and some cancers.  “Diseases of modern civilization,” they’re called.  Cleave and Yudkin wrote about this in the 1960s and ’70s, focusing more on the refined carbohydrates in industrial societies rather than the entire lifestyle.  I expect Gary Taubes would blame the processed carbs, too. 

Paleo diet proponents agree that grains are not a Paleolithic food.  The word “grain” isn’t in this article.  The authors don’t outline the sources of Paleolithic carbs: tubers and roots, fruits, nuts, and vegetables, I assume.  Legumes and milk are probably out of the question, too.

Low-carb diet and paleo diet advocates often allign themselves, even though this version of the paleo diet doesn’t appear to be very low-carb.  The two share an affinity for natural, whole foods, and an aversion to grains, milk, and legumes.  Otherwise I don’t see much overlap.

ResearchBlogging.orgA 2010 article by Kuipers et al (reference below) sugggests that the East African Paleolithic diet derived, on average, 25-29% of calories from protein, 30-39% from fat, and 39-40% from carbohydrate.  That qualifies as low-carb.  Modern Western percentages for protein, fat, and carb are 15%, 33%, and 50%, respectively.

You can make a good argument that these paleo concepts are healthy: high physical activity, nonsmoking, consumption of natural whole foods while minimizing simple sugars and refined starches.  The paleo community is convinced that grains and legumes are harmful; many others disagree.  Also debatable are the role of dairy, polyunsaturated to saturated fat ratio, low sodium, and high potassium.  Modern diets tend to be high-sodium and low-potassium, which may predispose to high blood pressure and heart trouble—diseases of modern civilization.

For more on the paleo diet and lifestyle, visit Free the Animal, Mark’s Daily Apple, and PaNu. 

Steve Parker, M.D.

Update December 18, 2010:  I found a reference suggesting that Paleolithic diets may have derived about a third—22 to 40%—of calories from carbohydrate, based on modern hunter-gatherer societies.  See the Cordain reference I added below.

Reference:

Kuipers, R., Luxwolda, M., Janneke Dijck-Brouwer, D., Eaton, S., Crawford, M., Cordain, L., & Muskiet, F. (2010). Estimated macronutrient and fatty acid intakes from an East African Paleolithic diet British Journal of Nutrition, 1-22 DOI: 10.1017/S0007114510002679.  Note that one of the authors is Loren Cordain.  Good discussion of various Paleolithic diets.

Eaton, S., Konner, M., & Shostak, M. (1988). Stone agers in the fast lane: Chronic degenerative diseases in evolutionary perspective The American Journal of Medicine, 84 (4), 739-749 DOI: 10.1016/0002-9343(88)90113-1

Cordain, L., et al.  Plant-animal subsistance ratios and macronutrient energy estimations in worldwide hunter-gatherer diets.  American Journal of Clinical Nutrition, 71 (2000): 682-692.

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October 11, 2010 · 7:18 AM

Paleo Diet for Heart Patients With Diabetes and Prediabetes

A Paleolithic diet lowered blood sugar levels better than a control diet in coronary heart disease patients with elevated blood sugars, according to Swedish researchers reporting in 2007.

About half of patients with coronary heart disease have abnormal glucose (blood sugar) metabolism.  Lindeberg and associates wondered if a Paleolithic diet (aka “Old Stone Age,” “caveman,” or ancestral human diet) would lead to improved blood sugar levels in heart patients, compared to healthy, Mediterranean-style, Western diet.

Methodology

Investigators at the University of Lund found enrolled 38 male heart patients—average age 61—patients and randomized them to either a paleo diet or a “consensus” (Mediterranean-like) diet to be followed for 12 weeks.  Average weight was 94 kg.  Nine participants dropped out before completing the study, so results are based on 29 participants.  All subjects had either prediabetes or type 2 diabetes (the majority) but none were taking medications to lower blood sugar.  Baseline hemoglobin A1c’s were around 4.8%.  Average fasting blood sugar was 125 mg/dl (6.9 mmol/l); average sugar two hours after 75 g of oral glucose was 160 mg/dl (8.9 mmol/l).

The paleo diet was based on lean meat, fish, fruits, leafy and cruciferous vegetables, root vegetables (potatoes limited to two or fewer medium-sized per day), eggs, and nuts (no grains, rice, dairy products, salt, or refined fats and sugar). 

The Mediterranean-like diet focused on low-fat dairy, whole grains, vegetables, fruits, potatoes, fatty fish, oils and margarines rich in monounsaturated fatty acids and alpha-linolenic acid. 

Both groups were allowed up to one glass of wine daily.

No effort was made to restrict total caloric intake with a goal of weight loss.

Results

Absolute carbohydrate consumption was 43% lower in the paleo group (134 g versus 231 g), and 23% lower in terms of total calorie consumption (40% versus 52%).  Glycemic load was 47% lower in the paleo group (65 versus 122), mostly reflecting lack of cereal grains.

The paleo group ate significantly more nuts, fruit, and vegetables.  The Mediterranean group ate significantly more cereal grains,oil, margarine, and dairy products.

Glucose control improved by 26% in the paleo group compared to 7% in the consensus group.  The improvement was statisically significant only in the paleo group.  The researchers believe the improvement was independent of energy consumption, glycemic load, and dietary carb/protein/fat percentages.

High fruit consumption inthe paleo group (493 g versus 252 g daily) didn’t seem to impair glucose tolerance. 

Hemoglobin A1c’s did not change or differ significantly between the groups.

Neither group showed a change in insulin sensitivity (HOMA-IR method).

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The authors’ bottom line:

In conclusion, we found marked improvement of glucose tolerance in ischemic heart disease patients with increased blood glucose or diabetes after advice to follow a Palaeolithic [sic] diet compared with a healthy Western diet.  The larger improvement of glucose tolerance in the Palaeolithic group was independent of energy intake and macronutrient composition, which suggests that avoiding Western foods is more important than counting calories, fat, carbohydrate or protein.  The study adds to the notion that healthy diets based on whole-grain cereals and low-fat dairy products are only the second best choice in the prevention and treatment of type 2 diabetes.

This was a small study; I consider it a promising pilot.  Results apply to men only, and perhaps only to Swedish men.  I have no reason to think they wouldn’t apply to women, too.  Who knows about other ethnic groups?

This study and the one I mention below are the only two studies I’ve seen that look at the paleo diet as applied to human diabetics.  If you know of others, please mention in the Comments section. 

The higher fruit consumption of the paleo group didn’t adversely affect glucose control, which is surprising.  Fruit is supposed to raise blood sugar.  At 493 grams a day, men in the paleo group ate almost seven times the average fruit intake of Swedish men (75 g/day).  Perhaps lack of adverse effect on glucose control here reflects that these diabetics and prediabetics were mild cases early in the course of the condition—diabetes tends to worsen over time.

ResearchBlogging.orgPresent day paleo and low-carb advocates share a degree of simpatico, mostly because of carbohydrate restriction—at least to some degree—by paleo dieters.  Both groups favor natural, relatively unprocessed foods.  Note that the average American eats 250-300 g of carbohydrates a day.  Total carb intake in the paleo group was 134 g (40% of calories) versus 231 g (55% of calories) in the Mediterranean-style diet.  Other versions of the paleo diet will yield different numbers, as will individual choices for various fruits and vegetables.  Forty percent of total energy consumption from carbs barely qualifies as low-carb. 

Study participants were mild, diet-controlled diabetics or prediabetics, not representative of the overall diabetic population, most of whom take drugs for it and have much higher hemoglobin A1c’s.

Lindeberg and associates in 2009 published results of a paleo diet versus standard diabetic diet trial in 13 diabetics.  Although a small trial (13 subjects, crossover design), it suggested advantages to the paleo diet in terms of heart disease risk factors and improved hemoglobin A1c.  Most participants were on glucose lowering drugs; none were on insulin.  Glucose levels were under fairly good control at the outset.  Compared to the standard diabetic diet, the Paleo diet yielded lower hemoglobin A1c’s (0.4% lower—absolute difference), lower trigylcerides, lower diastolic blood pressure, lower weight, lower body mass index, lower waist circumference, lower total energy (caloric) intake, and higher HDL cholesterol.  Glucose tolerance was the same for both diets.  Fasting blood sugars tended to decrease more on the Paleo diet, but did not reach statistical significance (p=0.08).

The paleo diet shows promise as a treatment or preventative for prediabetes and type 2 diabetes.  Only time will tell if it’s better than a low-carb Mediterranean diet or other low-carb diets. 

Steve Parker, M.D.

Reference: Lindeberg, S., Jönsson, T., Granfeldt, Y., Borgstrand, E., Soffman, J., Sjöström, K., & Ahrén, B. (2007). A Palaeolithic diet improves glucose tolerance more than a Mediterranean-like diet in individuals with ischaemic heart disease Diabetologia, 50 (9), 1795-1807 DOI: 10.1007/s00125-007-0716-y

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August 23, 2010 · 5:22 AM

2002 Atkins Diet at a Glance

Dr. Robert C. Atkins is the modern popularizer of low-carb dieting.  He was neither the first nor only low-carb advocate of the 20th century, but certainly the most influential in modern history in terms of followers.  His Dr. Atkins Diet Revolution was published in 1972 and sold millions of copies. 

Sir Isaac Newton wrote in 1676: “If I have seen further, it is by standing on the shoulders of giants.”  Twentieth century giants for Dr. Atkins include Frank Evans, Blake Donaldson (the original paleo diet guru?), Per Hansen, Alfred Pennington, and John Yudkin.  Most of these were physicians, by the way.  William Banting preceeded them, in the 19th century.

Dr. Atkins New Diet Revolution, published in 2002, was a huge seller then and maintains a respectable sales volume even now.  My impression is that Atkins Nutritionals, Inc., has replaced it with The New Atkins for a New You, which I reviewed last spring.  Enough people still follow DANDR that I need to stay familiar with it.  Here’s my brief summary of the phases.

Induction or Phase 1

  • Limit carbs to 20 g of “net carbs” daily for a minimum of two weeks.
  • “Net carbs” is the total carb count in grams, minus the fiber grams.
  • 3 cups of salad greens daily with olive oil/vingar or lemon juice OR 2 cups of salad greens and one cup of non-starchy cooked vegetables (e.g., broccoli or zucchini).
  • May also eat 3–4 ounces of aged cheese, a handful of olives, and half an avocado daily.

Ongoing Weight Loss (OWL) or Phase 2

  • Deliberate slowing of weight loss.
  • Gradually add back nutrient-rich carbs.
  • Increase net carbs weekly by just 5 g, by eating more veggies, nuts, seeds, even berries (this is where the “carb ladder” comes into play, adding carb groups in a specific order).
  • Some dieters can even add small amounts of beans and fruits other than berries, until weight loss stalls.  At that point, you drop back 5 g net carbs, to your Critical Carbohydrate Level for Losing (CCLL).

Pre-maintenance or Phase 3

  • Begins 5 or 10 pounds before reaching your weight goal.
  • Weight loss slows even more, taking at least 2 months to lose that last 10 pounds.
  • Can now add some starchy veggies like sweet potatoes, peas, whole grains.
  • If weight loss stops before goal, drop back down by 5-10 g net carbs, to your revised CCLL.

Lifetime Maintenance or Phase 4

  • Starts when you’ve been at goal weight for one month.
  • No more junk food, ever.
  • Stay vigilant for excessive carbs.  You may never be able to go back to whole grains or higher-carb fruits and vegetables.

Steve Parker, M.D.

PS: Gary Taubes reviews the history of low-carb diets in his masterpiece, Good Calories, Bad Calories.

Sir Isaac Newton
Head and shoulders portrait of man in black with shoulder-length gray hair, a large sharp nose, and an abstracted gaze

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July 28, 2010 · 9:32 AM

Paleo Diet and Diabetes: Improved Cardiovascular Risk Factors

Compared to a standard diabetic diet, a Paleolithic diet improves cardiovascular risk factors in type 2 diabetics, according to investigators at Lund University in Sweden.

Researchers compared the effects of a Paleo and a modern diabetic diet in 13 type 2 diabetic adults (10 men) with average hemoglobin A1c’s of 6.6% (under good control, then).  Most were on diabetic pills; none were on insulin.  So this was a small, exploratory, pilot study.  Each of the diabetics followed both diets for three months.

How Did the Diets Differ?

ResearchBlogging.orgCompared to the diabetic diet, the Paleo diet was mainly lower in cereals and dairy products, higher in fruits and vegetables, meat, and eggs.  The Paleo diet was lower in carbohydrates, glycemic load, and glycemic index.  Paleo vegetables were primarily leafy and cruciferous.  Root vegetables were allowed; up to 1 medium potato daily.  The Paleo diet also featured lean meats [why lean?], fish, eggs, and nuts, while forbidding refined fats, sugars, and beans.  Up to one glass of wine daily was allowed.

See the actual report for details of the diabetic diet, which seems to me to be similar to the diabetic diet recommended by most U.S. dietitians.

What Did the Researchers Find?

Compared to the diabetic diet, the Paleo diet yielded lower hemoglobin A1c’s (0.4% lower—absolute difference), lower trigylcerides, lower diastolic blood pressure, lower weight, lower body mass index, lower waist circumference, lower total energy (caloric) intake, and higher HDL cholesterol.  Glucose tolerance was the same for both diets.  Fasting blood sugars tended to decrease more on the Paleo diet, but did not reach statistical significance (p=0.08).

So What?

The greater improvement in multiple cardiovascular risk factors seen here suggests that the Paleo diet has potential to reduce the higher cardiovascular disease rates we see in diabetics.  Larger studies—more participants—are needed for confirmation.  Ultimately, we need data on hard clinical endpoints such as heart attacks, strokes, and death.

These diabetics had their blood sugars under fairly good control at baseline.  I wouldn’t be surprised if diabetics under poor control—hemoglobin A1c of 9%, for example—would see even greater improvements in risk factors as well as glucose levels while eating Paleo.

I see a fair amount of overlap between this version of the Paleo diet and Dr. Bernstein’s Diabetes Solution diet and the Low-Carb Mediterranean Diet. 

Steve Parker, M.D.

Reference:  Jönsson, T., Granfeldt, Y., Ahrén, B., Branell, U., Pålsson, G., Hansson, A., Söderström, M., & Lindeberg, S. (2009). Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study Cardiovascular Diabetology, 8 (1) DOI: 10.1186/1475-2840-8-35

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November 27, 2009 · 2:00 AM

What About the Paleo Diet?

Paleo diets have been increasingly popular over the last few years.  The idea is that, for optimal health, we should be eating the things that we are evolutionarily adapted to eat.  Those foods pre-date the onset of large-scale agriculture 10-12,000 years ago.  So grains and modern fruits and vegetables play little or no role in someone who has “gone paleo.”

My recollection from college courses years ago is that average lifespan in paleolithic times was perhaps 25-30 years, or less.  If you’re going to die at 25, it may not matter if you eat a lot of  wooly mammath, berries, insects, cholesterol, saturated fats, Doritos, Ding Dongs, or Cheetos.  The diseases of civilization we worry about today—coronary heart disease, high blood pressure, cancer, dementia, type 2 diabetes, etc.—don’t usually appear until after age 30.  Paleolithic Man worried more about starvation.

Jenny Ruhl, at her Diabetes Update blog, recently put much more critical thought than I into the concept of paleo diets.  Recommended reading.    

Steve Parker, M.D. 

Extra credit: 

For purposes of discussion, let’s assume that human evolution actually occurred over millions, or at least hundreds of thousands, of years.  In other words, assume that God didn’t make Adam and Eve in human form in one day.

The theory of evolution proposes that genes that allow an animal to live and reproduce more vigorously in a particular environment will be passed on to the animal’s offspring.  Nature will select those genes to spread through the animal population over time, assuming the environment doesn’t change.  The offspring with those genes will be able to compete with other animals more successfully for food, shelter, and mates.  Factors that promote the persistence and inheritance of specific genes are called “selection pressure.”

Here’s an example of selection pressure.  Remember when you were in grade school on the playground, some people could naturally run faster than others?  Were you one of the fast ones?  If you’ve never seen it for yourself, take my word for it: Some people are naturally gifted with athletic genes.

Let’s say you and I are outside collecting berries and nuts in paleolithic times.  A saber-toothed tiger spots us and charges, hungry for a meal.  You don’t have to outrun the tiger: you just have to outrun me.  I’m slower than you, and get eaten.   I can no longer pass on my slow-running genes to the next generation.  You live another day and pass on your fast-running genes to your children. 

Viola!  Natural selection, via selection pressure, has promoted your genes over mine.

[The tiger also passes on her genes since she was fast and smart enough to catch me, preventing starvation of her and her offspring.] 

[I’m 99% sure I wrote the preceeding few paragraphs originally about a year ago.  My notes, however, hint that they may have been written by Dr. J., a regular contributor at CalorieLab.  Dr. J., let me know if I’ve plagiarized you and I’ll give you full credit and delete my writing.]

The paleo diet rationale seems to be based on an evolutionary argument: Certain foods were available to us during 99% of our evolution, so our bodies are adapted to work optimally with them.  For example, humans/humanoids/higher primates who were not suited to the available food did not survive and reproduce, so their genes were not passed on to us.

For most of human existence, maximum lifespan was probably 25-30 years, on average. If that’s as long as you’re going to live, it may not matter much what you eat. Eat paleo, vegetarian, McDonald’s, Atkins, or Mediterranean. Most diet-related conditions except overweight and under-nutrition are not going to be an issue before age 30. 

[The modern paleos argue that infant and childhood mortality were extremely high in paleolithic times.  If you survived childhood, you could easily live to be 50+.]

But now we live to be 80, long enough for diet-related diseases to appear. We have cancer, heart attacks, and strokes that paleo man never saw because he died of trauma or infection or starvation. We even see the expression of genes that were not subjected to survival or selection pressure: Alzheimers disease, Huntingtons chorea, some breast cancers, etc.  People with genes for these diseases reproduce before the genes do their damage.

In other words, we carry genes that don’t matter if you die at age 30. If you live longer, they express themselves, and I believe we can modify their expression through diet and lifestyle. And not necessarily the paleo diet.

I’m still thinking it through.

For the other side of the argument, visit Mark’s Daily Apple, At Darwin’s Table, or read Dr. Loren Cordain’s The Paleo Diet.

-Steve

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