Can High-Carb, Low-Fat Be Healthy?

Compared to us moderns, many paleolithic and neolithic cultures who ate high-carbohydrate, starchy diets exhibited good health -- full sets of teeth and nicely developed noggins along with an absence of degenerative disease. A few of these cultures include the Kitavans (tubers, fruit, coconuts, & fish), the Kuna (plantain, yucca, kidney beans, fruit, & wild game/fish), and the traditional Peruvians (potatoes, quinoa, & guinea pigs -- seen in Nutrition & Physical Degeneration by Weston A. Price). As somebody who has adhered to a carbohydrate model (ala Taubes) in explaining present-day diseases and ill health, the fact that human beings can thrive on high-carbohydrate diets fascinates me. So let's explore this!

We'll begin by examining some of the obsevations of 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 (Matt Stone recently blogged about this subject and sparked my interest). 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. Through observations such as this, T.L. Cleave, like Weston A. Price before him, showed quite convincingly that refined foods are the cause of modern degenerative diseases.

But this isn't the entire story. If we are to think critically about Cleave's theory, we find that he oversimplified things a bit too much, lumping all detrimental foods into one category: refined carbohydrates. What this implies is that a person can consume all the whole grains, fruits, and potatoes he or she wants without experiencing the "diseases of civilization": diabetes, obesity, dental caries and crooked teeth, gastrointestinal ailments, heart disease, etc. As long we avoid sugar and refined grains, we'll live in good health, just as the rural Zulu did. Hmmm ... maybe.

While Cleave may or may not have been right about the general nature of refined carbs and their effects on human health, one glaring hitch in his theory is the fact that he overlooked something very simple: the chemical differences in carbohydrate foods and how these differences may be major factors in present-day diseases. In other words, it'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. Gary Taubes, author of Good Calories, Bad Calories, explains sugar's disaccharide nature in the body:

"The fructose will stimulate the liver to produce triglycerides, while the glucose will stimulate insulin secretion. And the glucose-induced insulin response in turn will prompt the liver to secrete even more triglycerides than it would from fructose alone, while the insulin will also elevate blood pressure apart from the effect of fructose." (p. 201)

The effects of fructose and glucose on the formation of AGEs (junk proteins in the body implicated in age-related chronic diseases) is also interesting. Taubes writes:

"Glucose [alone] ... is the least reactive of all sugars, the one least likely to attach itself without an enzyme to a nearby protein, which is the first step in the formation of AGEs. As it turns out, however, fructose is significantly more reactive in the bloodstream than glucose, and perhaps ten times more effective than glucose at inducing the cross-linking of proteins that leads to the cellular junk of [AGEs]. Fructose [induced-AGEs] ... seem more resistant to the body's disposal mechanisms than ... glucose. It also increases markedly the oxidation of LDL particles, which appears to be a necessary step in atherosclerosis." (p. 201)


Glucose -- the "least reactive of all sugars" -- appears to be the most ideal carbohydrate to consume if we are to avoid disease. Fructose seems to be the worst. Together, as sugar or honey or high-fructose-corn-syrup -- all glucose/fructose combinations -- they are the worst of the worst. It's kind of like putting Vin Diesel and Chuck Norris in an action flick together. Not good. You know somebody's gonna die.

So perhaps it is sugar (more specifically, fructose) and not refined foods like white flour or white rice (starches) that lead to our modern health ailments. It's hard to say for certain which food caused problems when evaluating primitive cultures as Cleave and Price did because, in every case examined, where there was smoke there was fire: white flour and sugar were being eaten at the same time. Yet, if it were all refined carbohydrates that lead to ill health, then how are we to explain healthy cultures on a diet centered around white rice such as the Japanese and Koreans? These cultures also consume animal foods in the form of fish, beef, and eggs -- all cholesterol-rich foods. Yet they have little heart disease. What's missing, which many industrialized cultures consume plenty of, is excessive sugar and high-fructose corn syrup (particularly in the form of soft drinks). Fructose intake in these countries has been very low traditionally, although it continues to grow from year to year.

I was actually in Seoul, Korea recently and noticed that almost everybody was slim and healthy-looking. The only obese Koreans I observed were a few children here and there. As consumption of soda, candy, and other fructose-sweetened products are increasing, displacing the starch calories in the diet, it appears that nation-wide obesity (and its slew of health complications) is on the rise.

With all of this to consider, we are left with a question: is fructose the culprit in present-day chronic disease? A man by the name of Dr. Richard Johnson theorizes that it is. His research strongly indicates this food as the main player in everything from diabetes to heart disease. The more and more I research it, the more I am convinced of such a theory. The Nutrition & Metabolism Society had this to say in a paper on fructose:

The alarming increase in fructose consumption may be an important contributor to the epidemic of obesity and insulin resistant diabetes in both pediatric and adult populations.

And this (italics mine):

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.


What I'm getting at here, in a long-winded, haphazard sort-of-way, is this working theory:

• Fructose in excessive quantities (i.e. standard American diet) is detrimental to human health.
• Starch alone is not detrimental to human health.
• A high-carbohydrate, starch-based diet -- that includes animal proteins & fats -- is a viable diet for long-term health.
• Human beings can thrive on a wide variety of diets -- a high-fructose diet does not seem to be one of them.

All of that being said, there is one important caveat to consider. If a person is already affected by diabetes and/or obesity or some other degenerative condition, a simple reduction in fructose may not provide health improvement. When the metabolism or equilibrium of the body is disturbed in such an unnatural way (theoretically from over-consumption of fructose), starch or any other carbohydrate may exacerbate the condition further. For these kinds of people, a low-carbohydrate diet may be the most therapeutic diet for the long-term.

I'd also like to add that, although fructose -- and not carbohydrates in general -- may be the true instigator in degenerative disease, a high-fat, low-carb diet has advantages that a high-carb diet does not: lipolysis, stable blood sugar, greater satiety, lack of hunger, more "protective" and nutrient-dense foods, and so on.

Not to mention the fact that the more carnivoristic tribes of ancient and contemporary history dispaly greater strength, minimal dental caries, and denser bones compared to agricultural, starch-eating peoples. Here's Dr. Price's observation in Africa:

In contrast with the Masai, the Kikuyu tribe...are charcterized by being primarily an agricultural people... [they] are not as tall as the Masai and physically they are much less rugged... teeth with caries [were] 5.5 percent ... 36.4 percent [of the population]. (pp. 138-139)

Therefore, although it's interesting that human beings can live in good health on a starch-based diet, I'll stick with a low-carb (100 grams or less), diet rich in animal products, thank you!

ADDENDUM TO THIS POST: Stephan from Whole Health Source challenged me on the notion that it is fructose alone that leads to the diseases of civilization. Read the comments section for our debate and witness Stephan -- the master of persuasion -- single-handedly alter my perspective on this issue ...