Are Low Carb Diets Over-rated for Health and Longevity? The Kitavan and Okinawa Diets.


In a previous article “Are Very Low Carb Diets Over-rated for Weight Loss“, we looked at comparing very popular diet approaches such as Atkins vs South Beach/Zone diets for the benefits of losing weight. What was the verdict? Well, we saw that with a same protein and calorie load, there was no advantages in weight loss for any…as they all worked. We also saw that having some days of higher carbohydrate intakes allowed for the hormone leptin to increase (which also ties in with metabolic rate). So now we are going to look at another aspect, health and longevity, when it comes to carbohydrate intake.

The Kitavan Diet

In a series of papers on the study of the native people from Kitava (island in Papua New Guinea), we come across a very healthy….and high carb eating society (Gasp! I’ll let the shock set in as many may have thought carbs are evil…but we’ll talk more about that later). Here’s an abstract from the study that sums up the results.

This study examined cross-sectional age relations of blood pressure, anthropometric indexes, serum lipids, and hemostatic variables in 203 subsistence horticulturists aged 20-86 y in Kitava, Trobriand Islands, Papua New Guinea. The population is characterized by extreme leanness (despite food abundance), low blood pressure, low plasma plasminogen activator inhibitor 1 activity, and rarity of cardiovascular disease. Tubers, fruit, fish, and coconut are dietary staples whereas dairy products, refined fat and sugar, cereals, and alcohol are absent and salt intake is low.

also Stephen @ Whole Health Source expanded a bit more on these numbers for the Kitavans, and makes an interesting relation…

Kitavans eat a diet of root vegetables, coconut, fruit, vegetables and fish and have undetectable levels of cardiovascular disease (CVD), stroke and overweight. Despite smoking like chimneys. 69% of their calories come from carbohydrate, 21% from fat and 10% from protein. This is essentially a carbohydrate-heavy version of what our paleolithic ancestors ate.

The first thing we can say is that a high intake of carbohydrate is not enough, by itself, to cause overweight or the diseases of civilization. It’s also not enough to cause insulin resistance.

Essentially you have a natural group of people who are as a whole very lean (although they are not starving, and eat plenty of calories), healthy, have good skin, strong teeth and suffer from virtually none of all the “diseases of civilization” (obesity, heart diseases, cancers) that are increasing at an alarming rate…oh yeah, did we mention they also eat a high intake of carbs and saturated fat (mostly from coconuts) in the process?

The Okinawa Diet

Next up we have the Okinawans, living off the coast of Japan and most studied for their history of health and longevity. They too are a group of people with excellent health, virtually no “diseases of civilization,” live long and functional (no “aging diseases” like loss of memory or movement)…all while having higher intake of calories from carbohydrates (upwards of 50-60%).

The Okinawa way isn’t a magic diet or exercise plan – it’s a lifestyle. There’s nothing complicated about it. Okinawa’s enjoy simple lives and they eat from the earth. That’s it. No plan, no time limit, no weighing, no beginning and no end. Okinawa’s have remarkably clean arteries and low cholesterol. Heart disease, breast cancer and prostate cancer are rare. This can be attributed to the Okinawans mostly plant based diet that includes fish and soy foods with a variety of vegetables and a moderate amounts of good fats. They consume locally grown vegetables and large quantities of tofu (high protein, low-fat, calcium, vitiman E) and seaweed (higher in vitamin and minerals than land vegetables).

from Associated Content story – The Okinawa Diet: The Key to Longevity?

What you do find in common with the Kitavans is the source of those carbs comes mainly all from vegetables (notably sweet potato). While there are also numbers for fat/protein that seem to change depending on who you ask….cutting through the %s, the sources are still whole and natural such as seafood or pork and cooking with lard (not vegetable oils).

Not All Carbs are Created Equal

Ok, we have seen just 2 examples of high carb eating societies of people that can live long and prosper (yes I know what I just said, must have been from seeing the new Star Trek movie). But the real debate should not be about exact %s of carbs in a diet, but WHAT are the sources of those carbs. If we take a graph from a previous article Obesity, Diabetes, and Other Diseases vs Food Trends in Pictures, we will “see” where the major changes have occured.

More calories and more carbs over time.

Carb sources increasing in cereal grains and sugar.

The pictures speak for themselves……calories have increased…..even though carbs have increased (while protein and fat has not)….the biggest increases of carbs now comes from cereal grains and sugar. Can we see a trend with increased obesity/disease and what is going on above?

Going into this a bit more, here is a good excerpt from Ryan @ Matters to Me who explains the difference in carbs:

T.L. Cleave, who wrote an important book called The Saccharine Disease. In this book, Cleave notes that the rural Zulu of Africa (in the 1950s) were in good health on a diet comprised of 90% carbohydrate calories. In contrast, the urban Zulu ate less carbohydrates (81%), yet had more diseases than the rural Zulu. Cleave concluded that the amount of carbs being eaten by the two groups didn’t matter so much as the types of carbs. This seemed to make all the difference: the rural population ate maize and root vegetables while the city-dwellers consumed refined, industrialized carbs, such as sugar and white flour.’s not as simple as whole foods vs. refined foods — it’s also a matter of the qualities of the foods. To illustrate this, let’s evaluate two of the evils that Cleave proclaims to be the cause of modern man’s health demise. On one hand we have white flour: a starch — also known chemically as a polysaccharide — which is broken down to glucose in the body. Sugar, on the other hand, is a disaccharide with a significant difference: it’s composed of glucose and fructose, which the body handles quite differently than it does starch.

A high flux of fructose to the liver, the main organ capable of metabolizing this simple carbohydrate, disturbs normal hepatic carbohydrate metabolism leading to two major consequences… perturbations in glucose metabolism and glucose uptake pathways, and a significantly enhanced rate of de novo lipogenesis and TG [triglyceride] synthesis, driven by the high flux of glycerol and acyl portions of TG molecules coming from fructose catabolism. These metabolic disturbances appear to underlie the induction of insulin resistance commonly observed with high fructose feeding in both humans and animal models.

As well, this is also a great observation made by Matt at 180 Degree Health:

So carbohydrates raise insulin levels temporarily to store away glucose into cells. Is that a bad thing? Of course it’s not. The rise and fall of insulin is no different than the rise and fall of your chest as your breathe.

The biggest flaw; however, is the idea that repeatedly raising insulin levels will somehow trigger insulin resistance over time. This is nonsense. The rural Zulu’s and modern day Kitavans, who both eat insulin-raising carbohydrates at every meal never went on to show signs of insulin resistance. They didn’t show signs of it because THEY WEREN’T INSULIN RESISTANT! Insulin resistance is something that appears to be triggered only in a reduced metabolic state – something I’ve reasonably concluded by following the work of Broda Barnes and Mark Starr – two men who reported never seeing a case of type II diabetes (severe insulin resistance) occur in someone with a closely monitored metabolism.

Since the only known substance that can reliably trigger insulin resistance in humans and animal subjects – something that was also introduced at the onset of modern disease – and something that has been associated with insulin resistance syndromes such as hypoglycemia, poor glucose tolerance testing, cavities and so on for going on a century is sugar. Not just any sugar, as straight glucose from starchy foods absolutely cannot induce insulin resistance – but fructose. Not surprisingly, the consumption of fructose is one of the two largest dietary changes to take place during mankind’s “ascent” to modernism.

So What’s the Real Answer?

When it comes to carbs, it is the source that seems to be of vital importance for health and longevity (which includes obesity that can come from a malfunctioning glucose metabolism). We have seen healthy societies with various %s (high and low) of carb intake but they all have one big thing in common…..they all eat natural “real foods”. They also have another thing in common, once people from their culture move into a more “modernized” food environment, then the health benefits seen previously decrease dramatically.

There doesn’t have to be just one way for health (and there usually never is). So don’t spend most of your time worrying about some magic macronutrient % and focus instead on getting your glucose metabolism fixed in the first place (especially your liver). Whether you choose to eat very low carb, moderate carb or higher carb… just keep these simple basic rules below in mind:

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