Tag Archives: ancestral diet

Classic Australian Aborigine Study on Return to Ancestral Diet and Lifestyle

Did you know kangaroo is edible?

The scientific article I review today is often cited by those who favor a Paleolithic diet for diabetics.  Cordain and Stefanson have written about it, for example.

Background

Urbanized Australian Aboriginal communities have a high prevalence of type 2 diabetes.   Kerin O’Dea writes:

The change from an urban to a traditional lifestyle involves several factors that directly affect insulin sensitivity: increased physical activity, reduced energy intake and weight loss, and changes in the overall dietary composition.  All of these factors improve insulin sensitivity and should, therefore, be of benefit to the insulin-resistant diabetic.

Methods

Ten urban type 2 diabetic and four nondiabetic full-blood Aborigines agreed to revert to their traditional lifestyle as hunter-gatherers in an isolated region of Australia for seven weeks.  Average age was 53.  Half of them were moderate to heavy alcohol drinkers.  Average diabetic weight was 82 kg (180 lb); nondiabetics averaged 77 kg (169 lb).  There were equal numbers of men and omen.  None of the diabetics was on insulin, and only one was on an oral diabetic drug (a sulfonylurea). 

Ayers Rock, Uluru National Park, Australia

The study was carried out at Pantijan, the traditional land of these Aborigines.  It’s a day-and-a-half drive in a four-wheel vehicle from Derby.  At least it was in 1984.

For seven weeks, the participants ate only what they hunted or collected.  Diet composition was dependent on whether they were travelling to the homeland (1.5 weeks), at the coastal location (2 weeks), or inland on the river (3.5 weeks). Protein sources were mainly beef, kangaroo, fish, birds, crocodiles, and turtles.  Carboydrate content ranged from under 5% to 33%.  Protein content varied from 50 to 80%.  Fat was 13 to 40%.  So, very high protein and low-carb.  Carb sources were yams, honey, and figs.  Yams were the predominant carb source.  They also eat yabbies (shrimp or crayfish (“crawdads” in Oklahoma)).  Average energy intake was a very low 1,200 calories a day. 

The author implies this was the traditional Aboriginal diet.

What did they eat back home in the city? 

The main dietary components were flour, sugar, rice, carbonated drinks, alcoholic drinks (beer and port), powdered milk, cheap fatty meat, potatoes, onions, and variable contributions of other fresh fruit and vegetables. 

O’Dea estimates a macronutrient breakdown of 50% carb, 40% fat, and 10% protein (similar to the Standard American Diet, then).

What Did O’Dea Find Out?

Everyone lost weight, a group average of 8 kg (18 lb) over the seven weeks.

Fasting blood sugars fell in the diabetics from 11.6 mmol/l to 6.6 mmol/l (209 to 119 mg/dl).  After-meal blood sugars also fell dramatically.

Fasting insulin levels fell from 23 to 12 mU/l.

Fasting triglycerides fell drastically. 

HDL cholesterol fell significantly, whereas LDL cholesterol tended to rise.

So What?

How often do you see a scientific article with just one author?  Rarely, these days.

The investigator wrote that, “Under the conditions of the study it is difficult to separate out effects of dietary composition, low energy intake, and weight loss.”

O’Dea estimates that experimental activity levels were probably higher than in the urban setting, but not dramatically more so.  (He was with the participants throughout the experiment.)

The main carbohydrate sources in this ancestral diet were yams, honey, and figs.  Modern Australian honey is probably similar to the honey of 100,000 years ago.  But what about yams and figs? 

These folks had to have been eating twice as many calories, at least, back in their urban environment.  O’Dea didn’t comment on how well the participants tolerated calorie restriction.  Did they complain?  Did they eat to satiety?  They had no access to food other than what they could hunt and gather.  Was food in short supply?  It’s not documented.  You’d think O’Dea would mention these issues if they were a problem. 

This particular ancestral diet was extremely high in protein: 50–80% of calories.  (Eaton and Konner suggest that an average ancestral diet provides only 25–30% of total calories from protein.  A typical modern high-protein diet derives about 30% of calories from protein, compared with 15–18% in the standard American diet.)  Protein helps combat hunger.  But halving caloric intake for seven weeks is extreme.  Don’t believe me?  Just try it.  This degree of caloric restriction by itself would tend to lower blood sugar levels and body weight in most humans, regardless of macronutrient ratios and ethnicity.

I know nothing about Australian Aborigines as an ethnic and genetic group.  Is their diabetes similar to European diabetes?  Pima Indian diabetes?   

O’Dea never called the study diet Paleolithic, because it wasn’t. It was a modern hunter-gatherer diet eaten by rural, isolated Australian Aboriginal communities.

This calorie-restricted, very-high-protein, natural diet was very effective for weight loss and blood sugar control in this tiny, seven-week study on a specific ethnic population.  I bet the caloric restriction was the most effective component of the lifestyle change.  Restriction of refined sugars and starches also helped. 

This ancestral diet was beneficial for a few Australian Aborigines.  Are the lessons widely applicable?  Not yet.  As they say, “further studies are needed.”  You can’t just cite this study to say that paleo diets are healthy for diabetics.

It does jibe with plenty of other research that shows severe calorie restriction leads to weight loss and lower blood sugar levels.

Steve Parker, M.D.

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

Random Thoughts On Paleo Eating For People With Diabetes

Not really pertinent, but I like buffalo

I was interviewed  yesterday by Amy Stockwell Mercer, author of Smart Woman’s Guide to Diabetes.  All I knew beforehand was that she was interested in my thoughts on the paleo diet as applied to diabetes.

In preparation, I collected some random thoughts and did a little research.

What’s the paleo diet?

Fresh, minimally processed food.  Meat (lean or not? supermarket vs yuppiefied?), poultry, eggs, fish, leafy greens and other vegetables, nuts, berries, fruit, and probably tubers.

Non-paleo: highly processed, grains, refined sugars, industrial plant/seed oils, legumes, milk, cheese, yogurt, salt, alcohol.

Is the paleo diet deficient in any nutrients?

A quick scan of Loren Cordain’s website found mention of possible calcium and vitamin D deficits.  Paleoistas will get vitamin D via sun exposure and fish (especially cold-water fatty fish).  Obtain calcium from broccoli, kale, sardines, almonds, collards.  (I wonder if the Recommended Dietary Allowance for calcium is set too high.)

What About Carbohydrates and Diabetes and the Paleo Diet?

Diabetes is a disorder of carbohydrate metabolism.  In a way, it’s an intolerance of carbohydrates.  In type 1 diabetes, there’s a total or near-total lack of insulin production on an autoimmune basis.  In type 2 diabetes, the body’s insulin just isn’t working adequately; insulin production can be high, normal or low.  In both cases, ingested carbohydrates can’t be processed in a normal healthy way, so they stack up in the bloodstream as high blood sugars.  If not addressed adequately, high blood glucose levels sooner or later will poison body tissues .  Sooner in type 1, later in type 2.  (Yes, this is a gross over-simplification.) 

Gluten-rich Neolithic food

If you’re intolerant of lactose or gluten, you avoid those.  If you’re intolerant of carbohydrates, you could avoid eating them, or take drugs to help you overcome your intolerance.  Type 1 diabetics must take insulin.  Insulin’s more optional for type 2’s.  We have 11 classes of drugs to treat type 2 diabetes; we don’t know the potential adverse effects of most of these drugs.  Already, three diabetes drugs have been taken off the U.S. market or severely restricted due to unacceptable toxicity: phenformin, troglitazone, and rosiglitazone. 

Humans need two “essential fatty acids” and nine “essential” amino acids derived from proteins.  “Essential” means we can’t be healthy and live long without them.   Our bodies can’t synthesize them.  On the other hand, there are no essential carbohydrates.  Our bodies can make all the carbohydrate (mainly glucose) we need.

Since there are no essential carbohydrates, and we know little about the long-term adverse side effects of many of the diabetes drugs, I favor carbohydrate restriction for people with carbohydrate intolerance.  (To be clear, insulin is safe, indeed life-saving, for those with type 1 diabetes.)

That being said, let’s think about the Standard American Diet (SAD) eaten by an adult.  It provides an average of 2673 calories a day (not accounting for wastage of calories in restaurants; 2250 cals/day is probably a more accurate figure for actual consumption).  Added sugars provide 459 of those calories, or 17% of the total.  Grains provide 625 calories, or 23% of the total.  Most of those sugars and grains are in processed, commercial foods.  So added sugars and grains provide 40% of the total calories in the SAD.  Remember, we need good insulin action to process these carbs, which is a problem for diabetics.  (Figures are from an April 5, 2011, infographic at Civil Eats.)

Anyone going from the SAD to pure Paleo eating will be drastically reducing intake of added sugars and grains, our current major sources of carbohydrate.  Question is, what will they replace those calories with? 

That’s why I gave a thumbnail sketch of the paleo diet above. Take a gander and you’ll see lots of low-carb and no-carb options, along with some carb options. For folks with carbohydrate intolerance, I’d favor lower-carb veggies and judicious amounts of fruits, berries, and higher-carb veggies and

Will these cause bladder cancer? Pancreatitis?

tubers.  “Judicious” depends on the individual, considering factors such as degree of residual insulin production, insulin sensitivity, the need to lose excess weight, and desire to avoid diabetes drugs.

Compared to the standard “diabetic diet” (what’s that?) and the Standard American Diet, switching to paleo should lower the glycemic index and glycemic load of the diet.  theoretically, that should help with blood sugar control.

A well-designed low-carb paleo diet would likely have at least twice as much fiber as the typical American diet, which would also tend to limit high blood sugar excursions.

In general, I favor a carbohydrate-restricted paleo diet for those with diabetes who have already decided to “go paleo.”  I’m not endorsing any paleo diet for anyone with diabetes at this point—I’m still doing my research.  But if you’re going to do it, I’d keep it lower-carb.  It has a lot of potential.

Are There Any Immediate Dangers for a Person With Diabetes Switching to the Paleo Diet?

It depends on three things: 1) current diet, and 2) current drug therapy, and 3) the particular version of paleo diet followed. 

Remember, the Standard American Diet provides 40% of total calories as added sugars and grains (nearly all highly refined).  Switching from SAD to a low-carb paleo diet will cut carb intake  and glycemic load substantially, raising the risk of hypoglycemia if the person is taking certain drugs.

Drugs with potential to cause hypoglycemia include insulin, sulfonylureas, meglitinides, pramlintide, and perhaps thiazolidinediones.

Who knows about carb content of the standard “diabetic diet”?  Contrary to popular belief, there is no monolithic “diabetic diet.”  There is no ADA diet (American Diabetes Association).  My impression, however, is that the ADA favors relatively high carbohydrate consumption, perhaps 45-60% of total calories.  Switching to low-carb paleo could definitely cause hypoglycemia in those taking the aforementioned drugs.

One way to avoid diet-induced hypoglycemia is to reduce the diabetic drug dose.

A type 2 overweight diabetic eating a Standard American Diet—and I know there are many out there—would tend to see lower glucose levels by switching to probably any of the popular paleo diets.  Be ready for hypoglycemia if you take those drugs.

Paleo diets are not necessarily low-carb.  Konner and Eaton estimate that ancestral hunter-gatherers obtained 35 to 40% of total calories from carbohydrates.  I’ve seen other estimates as low as 22%.  Reality likely falls between 22 and 65%.  When pressed for a brief answer as to how many carbohydrate calories are in the paleo diet, I say “about a third of the total.”  By comparison, the typical U.S. diet provides 50% of calories from carbohydrate.

Someone could end up with a high-carb paleo diet easily, by emphasizing tubers (e.g., potatoes), higher-carb vegetables, fruits, berries, and nuts (especially cashews). Compared with the SAD, this could cause higher or lower blood sugars, or no net change.

A diabetic on a Bernstein-style diet or Ketogenic Mediterranean Diet (both very-low-carb) but switching to paleo or low-carb paleo (50-150 g?) would see elevated blood sugars.  Perhaps very high glucoses.

Any person with diabetes making a change in diet should do it in consultation with a personal physician or other qualified healthcare professional familiar with their case.

Steve Parker, M.D.

Fun Facts!

  • A typical carbonated soda contain the equivalent of 10 tsp (50 ml) of sugar.
  • The typical U.S. adult eats 30 tsp  (150 ml) daily of added sweeteners and sugars.
  • U.S total grain product consumption was at record lows in the 1970s, at 138 pounds per person.  By 2000, grain consumption was up by 45%, to 200 pounds per person.
  • Total caloric sweetener consumption (by dry weight) was 110 pounds per person in the  1950s.  By 2000, it was up 39% to 150 pounds.
  • Between 1970 and 2003, consumption of added fats and oils rose by 63%, from 53 to 85 pounds.  [How tasty would that be without starches and sugars?  Not very.]
  • In 2008, “added fat” calories in the U.S. adult diet were 641 (24% of total calories).

Fun Facts provided by the U.S. Department of Agriculture. 

(The paleo diet is also referred to as the Paleolithic, Old Stone Age, Stone Age, Ancestral, Hunter-Gatherer, or Caveman diet.)