Which Diet?


Perceptions of diet in the Western World have changed in half a century.

One result is a confusing mass of information, from both valid and invalid sources.

Some opinion has evolved in scientific institutions, with the implied credibility of that origin. Some has been evolved by charlatans, both within and without the field of journalism.

Those philosophies originating within scientific institutions, and dutifully perpetuated to the medical and dietetic professions often had dubious origins, some frankly wild guesses.  Some of the claims to statistical certainty must be taken with caution, and there are suspicions that BigPharma has been responsible for some distortions of that process.

Much advice about food appropriate for health has been given. Much of that has been based upon (often marginal) statistics. Many are deduced from self-reporting surveys. However the variables are so great that it is impossible to accommodate these into meaningful statistics. A few of these variables include quantum of food, types of mixtures of food, frequency of these foods, plus multiple variables related to micro-nutrients ingested simultaneously, and more.

What is the Aim of this Booklet?

The aim is to try to give a better understanding of some of the reasons behind eating patterns, and perhaps clarify the perplexing variety of opinion about diet.

This attempt to rationalise is not scientific precision.  This is not peer reviewed but critical responses will be welcomed.  This might not resist the rigor of an editor.  These are simply observations intended to spur thought and look laterally.

Abundant food

Abundant food is now available (in the Western World), in contrast to the period before World War two. Up to then the amount of food was limited and choice even more so. Previously many were lucky to go to bed with a full stomach. Since 1946 food production per capita has increased by 40%.

Since then, and this is recent past, almost unlimited food has become available to most, and the choice of food increased by huge factors. Further the food industry, which includes the retail market and multiple extensions such as the packaging and advertising. Pre-prepared foods have become standard, and recreational eating has become part of daily life, and the economy. Agricultural practices have changed, and new cultivars have become available in a way previously unimagined.

Perhaps not surprisingly, the influence of abundance on choices, increased disposable income and consequently on health are profound.

Can Optimal Diet vary with Context?

Biologically it seems likely that diets were driven by the context in which parcels of humans lived prehistorically. This allowed a slow adaptation of varied human groups, with their varied cultures Migration was probably slow and limited, which allowed an adaptation to the context of habitat, and to modify the biology.

Economics of Food.

Like Big Pharma, Big Food began to dominate and control diet in the present era. Powerful tools of advertising, preservation and immediate availability, have altered human dietary behaviour in the 20C.

Not surprisingly some people are now perplexed. Some have developed concern at the change of disease patterns and the changes in appearance.

Pathology and Ill-health

It is true that obesity has existed throughout history, but this was the exception, just as wealth and finery were exceptional.

However these alterations in human biology towards obesity are now becoming the norm, as are the illnesses and deaths of affluent excess.

What Sources of Information are Available?

When in doubt, it has been said, look in the instruction book. The instruction book for  animals (including the human)  exists in the animal. It is the inclination to eat some foods and the abhorrence of others.

The changes of context and the deviations from the “natural” have now left us without the instruction book. Therefore, one step back is to consider the design specifications.

Design Specification.

Unfortunately the animal-machine-design did not make provision for the possibility of limitless food, or great food variety, or changes cultivars.

Since selection by appetite is probably flawed, and one is left guessing (somewhat) about the design specification. That is what is addressed here.

But before that, if one wants to live longer, the method has been (scientifically) available for the better part of a century. Simply, eat less. Eat less than your appetite drive. Eat less than your cohorts.

If one wants to reduce the chance of cancers, eat less smoked preserved food.

But let us look at design. Suppose humans were to be designed from scratch, which fuels (i.e. foods) should be selected, bearing in mind the limitations of availability, and knowing that the human is a mobile device with defined functional requirements and a limited life-span? Consider these options, and consider how they fit with current eating patterns:

Fat is probably the most desirable and quintessential choice of fuel-food for humans. Fat has the highest calorific gain per unit mass of all foodstuffs whilst it has a low energy cost for ingestion and digestion. It is the most cost effective source of energy.  Fat is the supreme appetizer, driving the animal to eat it.  Yet fat has powerful negative feedback mechanisms.  Therefore, although fat stimulates appetite it also produces satiation relatively rapidly. Rapid satiation allows food to be spread to the entire pack, in keeping with expectations of le milieu exterior which demands survival of the group, not the greedy individual. However the satiation effect of fat can be strongly altered by salt.  Therefore, salted fat and perhaps salted protein can become “compulsive” foods, inducing the eater to keep eating until gorged.  So we have yet another factor, the “additions” to food which induce compulsive feeding, prompted by those intent on making money out of food. Fat carries essential vitamins, and is therefore an essential to the diet.

Protein is probably neutral tasting without the fat and salt: is not particularly palatable and does not have the “addictive” quality of carbohydrate. But it contains “essential” components which the human cannot manufacture, including amino-acids and vitamin C (curiously a “water-soluble” vitamin). It is also firmly mechanically bound to fat, and often inseparable from it.

Carbohydrate, was probably not particularly attractive to early humans.  Yes, I know that some carbohydrates, the sugary carbohydrates, are exceedingly attractive today.  But in primitive societies, all carbohydrates were not attractive.  Pure sugar is a relatively new evolution. The current sweet fruits and even corn and potatoes are the product of intentional selective breeding to make those carbohydrates more palatable.

The metabolisms of carbohydrate, the sugars, are again very different from fat, because the same metabolic pathways are used for both the anabolism and the catabolism of carbohydrate. The control of carbohydrate metabolism lies outside the direct metabolic pathways, relying on end-organ control. These include insulin receptors.   This is different from fat metabolism where the anabolic and catabolic pathways are different, and so allowing feed-back to curb appetite and metabolic direction.

Carbohydrate’s prime quality is that it is cheap.  As a consequence commerce has “wrapped” carbohydrate in both fats and sugar in order to make it compulsive eating at a cheap price.  Amongst the most tempting ingestants are those that have both sugar and fat, as in chocolate.

Refined and manufacturer altered carbohydrate once ingested, prompt the desire to keep on eating it. Carbohydrate can have a long shelf life, is easily stored and so lends itself to easy snacking. No surprise that it is perfect to fuel “habituation eating”, and ultimately obesity.

Sugar is impregnated into cakes, carbohydrates or spread on the top as icing.  Fat is used as a layer to make bland carbohydrates or even carbohydrates and protein more palatable, as in deep fried foods – where salt is added for good measure. Cheap beans are made more palatable for sale by adding the salt and sugar of ketchup. Salt is impregnated into carbohydrate ( chips and French fries).

Changing carbohydrates. The vegetative production of carbohydrate has been substantially altered over the centuries.  In broad terms, carbohydrate was not palatable and not an attractive ingestant but it has been altered to be more enticing, primarily by increasing the sugar.  The fruit which we eat now has been selectively bred and is considerably sweeter than the fruit provided to primitive man (as a generalisation).  Even substances like corn have been made softer, sweeter and probably fattier by selective breeding.  More recently the changes of selective breeding have been accelerated by genetic engineering, but the perspective must be retained that genetic engineering has had less influence on palatability than selective breeding.  Much of genetic engineering relates to enhanced production efficiency with greater yields and resistance to adverse events such as drought and disease.  Shelf life has been improved and methods of removing contaminants (including contaminating infections and their by-products such as the flavo-proteins) have been forcibly and successfully addressed.

Probably the single most influential change has been the enhanced production of sugars.  Not only has the feedstock been made sweeter but the sugars themselves have been produced in enormous quantities as a standalones or additives.

Water, the foundation nutrient.  Animals and plants are far more dependent upon water than food, and will die of thirst long before dying of hunger,

In recent times many children are trained into metabolic confusion about thirst. This is because the water offered to them is laced with calories, primarily sugar and some metabolically noxious colourants. They the capability to distinguish between thirst and  hunger. When thirsty they might attempt to satisfy themselves by choosing “food” rather than fluid (sugar laden drinks, ice cream ). The outcome is hyper-caloric habituation.

Is it what is eaten or is it which combination that is important?

It might not be what you eat, but which combination one eats, that influences the health or disease of individuals.  There is some evidence that individuals like to eat the same food and will repeat eating that ingestant by choice.

“Humans like variety, humans need variety, and humans need a balanced diet”.  This may not have been the case with evolutionary man and it is certainly not the case with many animals.  Those animals can adapt to a particular foodstuff (obviously one that is available) and then continue eating that foodstuff by choice, even where alternatives become available.

The legend has arisen that individuals need a “mixed and balanced” diet.  As far as I am aware there is no evidence that this mixing needs to occur in the same meal.  True enough, one needs the vitamins and one needs the different proteins, fat and carbohydrate.  But does one need them simultaneously, wrapped around each other and made into tempting compotes?

Metabolic pathways

Metabolic pathways are the succession of chemical changes which convert one compound into another within the body. There are many: the entire number is probably not known and there are even more subsidiary and partial pathways by which biochemical processes proceed.  The pathways themselves are highly complex and depend upon routing through enzymes, co-enzymes as well accelerating and retarding factors. These routes change with different ingestants and external factors, even unlikely factors such as sunlight, in their complexity as a manufactory.

That these pathways can “learn” to take increased loads and can be trained to be more efficient and act more rapidly can be demonstrated in enhanced metabolism (“adaption”) of drugs and alcohol. Mitochondria engineer these intra-cellular modifications. This “training” might be the basis of athletic fitness (other factors such as muscle hypertrophy and muscle memory training are clearly also involved)

At simplest these pathways allow the assembly of those carbon based substances which form biological structures and allow degradation of material in order to provide energy. Disassembly of “organic” components to be reused in growth, repair, adaptation and excretion of “waste” is further role.

The railway analogy.

These biochemical pathways can be compared with complex railroad transit systems having junctions, points, lay-bys, regular sites of loading and unloading as well as the ability to regulate the load carried.

Many disease processes can be attributed to aberrations or failures of these metabolic “transport systems”.  Many diseases probably occur as a result of unknown happenings in these biochemical pathways.

Therefore, if one considers nutrition, one must consider these pathways, by which ingestants are disassembled, transported through (usually) the intestinal boundaries.  In themselves, these intestinal transits are highly complex, selective and prone to disease or abnormality.

21st century humans ingest in very different fashions from their evolutionary predecessors.  Ingestants have changed and have become complex by a variety of manufacturing and industrial events.  What then is the likelihood that the biochemical pathways have become altered, “confused” or overloaded beyond design specification?  This would seem not only highly likely but to be accepted and guaranteed.

Therefore, let us look at the common ingestants, the basic feedstock of humans, and the source of their fuel-energy dynamics.  Preeminent is carbohydrate.   For practical purposes all carbohydrate is grown as vegetation.  ( some sugars, exemplified by lactose, have animal origins) So important is food to human behaviour and existence that the wealthiest nations have, as their economic foundation, successful agricultural industries.

Industrialisation of Food. One result  of the “industrialisation” of food is that carbohydrate has been changed from the highly fibrous and cellulose wrapped (and therefore relatively unpalatable). Carbohydrate is now an easily accessed and addictively attractive substance with a long shelf life, made immediately available to millions of households. Because it does not deteriorate (assisted by long-life additives) it can be snacked at will, on impulse, as a consolation or a habit from the readily available stock in most households.

Other attracting and seductive foods have been mixed with carbohydrate to make carbohydrate relatively inexpensive and highly, if not addictively, desirable. Eminent are salt and fat.  Carbohydrate has been introduced into the diet of infants and children in this way and so probably changing their taste and purchase preferences forever.  One has only to look at breakfast cereals where the bulk is cheap carbohydrate but “flavoured” (and for the word flavour think behaviour changing) with the two most powerful enticers, fat and sugar.

Of concern also is the industrial removal of substances from food, such as “de-bittering”. That bitterness, nature’s negative attractant is caused by a variety of substances such as tannins. These would “normally” have the effect of binding molecules and making some foods non-digestible. Removing them will increase absorbable calories, and reduce colon bulk. There is evidence that some of these lost “bitter” components could prevent cancers.

Disease pathways. Gout, as is well known is the result of an aberrant metabolic pathway – part genetic, part contextual. Atheroma demonstrates an analogy with gout. The “pathological substance” of atheroma is cholesterol. This is a normal constituent of the biology of humans. Cholesterol plays a vital part in the structure of the neurological system, and much more. To suggest that cholesterol can be removed from human metabolism (by reducing intake) is ludicrous. What needs to be corrected is the deposition in arterial walls. Now look at gout where the pathological substance is uric acid – a perfectly normal constituent of human metabolism. In humans uric acid is converted, by a metabolic pathway, to urea. Urea is soluble and readily excreted in urine. However if the metabolic pathway is disrupted, uric acid accumulates and disease (gout) results. This metabolic pathway disruption can be caused by genetic factors, overload by ingestion, and other physical factors. Not unlike atheroma.

The physical factor in atheroma is reflected by vascular damage by high pressures of blood, areas of blood turbulence and perhaps loss of blood vessel wall elasticity. Yet another factor might be direct damage to the arterial wall by tiny shards of metal generated in the opening of metal cans. This might explain the high incidence of atheroma in young GIs in Viet Nam: They lived on canned food, probably ingesting these metal shards which might be expected to damage arterial walls, especially in areas of is high turbulence of the blood.

Over eating. Could excessive food volume alone confuse the metabolic pathways and produce disease? Could mixing different types of food taken at the same meal confuse the metabolic pathways and produce disease?


Calories? What about dieting? The analogy with the law of physics, “matter cannot be created or destroyed”, has led to a dieting illusion. It is often held that losing weight can be worked on the basis “calories in – calories out (by exercise)”. Hence calorie counting. But it can be shown that is invalid as a way of reducing fat. More likely exercise (which undoubtedly can lead to loss of weight, particularly fat loss) changes the metabolic pathways (perhaps from glucose catabolism to fat catabolism), allowing selective burn of fat.

Jon Driver-Jowitt



About jp

Orthopaedic Surgeon
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