Tag Archives: Industrial Revolution

How Did the Agricultural and Industrial Revolutions Change Human Diets?

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With the advent of the Agricultural Revolution 10,000 years ago, mankind took a giant leap away from two million years of evolutionary adaptation. The Industrial Revolution that started in the late 18th century—about 240 years ago—was yet another watershed event. The Agricultural Revolution marks the end of the Old Stone Age and the start of the Neolithic period. The Neolithic ended four to six thousand years ago, replaced by the Bronze Age (or Iron Age in some areas).

EFFECTS OF THE AGRICULTURAL REVOLUTION

The Agricultural Revolution refers to farming the land on a large scale, and all that entails: gathering and planting seeds, nurturing the soil, breeding plants for desirable traits, storing crops, processing plants to maximize digestibility, domesticating wild animals and enhancing them by selective breeding, setting down roots in one geographic location, etc. The revolution allowed for the expansion of reliable food supplies and an explosion of human populations. Less time was needed for hunting and foraging, allowing for the development of advanced cultures.

It wasn’t all sunshine and roses, however. We have evidence that human health deteriorated as a result of the revolution. For instance, some populations declined in height and dental health.

EFFECTS OF THE INDUSTRIAL REVOLUTION

The Industrial Revolution starting in the late 18th century brought its own changes to our diet. Progressive industrialization and affluence changed the composition of our “energy foods.” For instance, peasants in poor developing countries derive about 75% of their calories from high-fiber starchy foods. With modernization, fiber-free fats and sugars become the source of 60% of calories. U.S. consumption of cereal fiber decreased by 90% between 1880 and 1976. In addition to lower fiber content, refined wheat products also had fewer vitamins and other micronutrients. Machinery allowed the production of margarine and vegetable oils. Sugar imports and snacking increased in the Western world.

Obesity suddenly became very common in the upper classes of Europe and England toward the end of the 17th century and even more so in the 18th. Weights also increased throughout populations of developed countries. For instance, if we look at U.S. men of average height between the ages of 30 to 34, average weights were 148 lb (66 kg) in 1863, but were up to 170 lb (77 kg) in 1963. Our current obesity epidemic didn’t even start until around 1970.

Let’s look at a few major U.S. diet changes from 1860 to 1975. Energy derived from protein rose from 12% to 14–15%. Energy from fat rose from 25 to 42% of calories. Energy from starches fell from 53 to 22%. Calories from sugar rose from 10 to 24%. Total carbohydrate calories fell from 63 to 46%.

It only takes a few decades to see major changes in a population’s food consumption. For instance, U.S. per capita consumption of salad and cooking oils increased from 21.2 pounds per person in 1980 to 54.3 pounds per person in 2008 (USDA data). I refer to these oils as industrial seed oils, and they include soybean, corn, and sunflower oil. We’re not entirely sure what effect these have on health. Some suspect they are related to obesity, heart disease, and other “diseases of civilization.” Per capita soybean oil consumption in the U.S. increased over a thousand-fold between 1909 and 1999, to 7.4% of total calories. It’s in many of our processed foods. Linoleic acid is a predominant omega-6 fatty acid in seed oils. Linoleic acid consumption increased by 200% in the last century. Thanks to increasing omega-6 fatty acid consumption, the omega-6/omega-3 ratio increased from 5.4:1 to 9.6:1 between 1909 and 2009. (Reference: Blasbalg TL, Hibbeln JR, Ramsden CE, Majchrzak SF, Rawlings RR. “Changes in consumption of omega-3 and omega-6 fatty acids in the United States during the 20th century.” Am J Clin Nutr. 2011 May;93(5):950-62. doi: 10.3945/ajcn.110.006643. Epub 2011 Mar 2.)

The Industrial Revolution also introduced into our diets large amounts of man-made trans-fats, which are highly detrimental to cardiovascular health. Public outcry has lead to diminishing amounts of dietary trans-fats over the last decade.

An occasional teaspoon of sugar probably won't hurt you

Added sugars: table sugar in coffee, high-fructose corn syrup in ketchup

At his Whole Health Source blog, Dr. Stephan Guyenet and Jeremy Landen produced a graph of U.S. sugar consumption from 1822 to 2005. Dr. Guyenet wrote, “It’s a remarkably straight line, increasing steadily from 6.3 pounds (2.9 kg) per person per year in 1822 to a maximum of 107.7 pounds (49 kg) per person per year in 1999. Wrap your brain around this: in 1822, we ate the amount of added sugar in one 12 ounce can of soda (360 ml) every five days, while today we eat that much sugar every seven hours.” Note that added sugars overwhelmingly supply only one nutrient: pure carbohydrate without vitamins, minerals, antioxidants, protein, fat, etc.

 

Think about the typical Western or Standard American Diet (SAD) eaten by an adult these days. 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. That’s a huge change from the diet of our prehistoric ancestors. Remember, we need good insulin action to process these carbohydrates, which is a problem for diabetics. 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. They’ll be replacing them with foods that generally require less insulin for processing. (Figures are from an April 5, 2011, infographic at Civil Eats: http://www.civileats.com.)

FUN FACTS! (from the U.S. Dept. of Agriculture)

  • A typical carbonated soda contains the equivalent of 10 tsp (50 ml) of table 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 2008, 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).

Steve Parker, M.D.

Notable Quotes From Kuipers’ “Multidisciplinary Reconstruction of Palaeolithic Nutrition”

Australian Aborigine in Swamp Darwin

I scored of copy of “A multidisciplinary reconstruction of Palaeolithic nutrition that holds promise for the prevention and treatment of diseases of civilisation” by RS Kuipers, JCA Joordens, and FAJ Muskiet. I’m not going to review it here. I’m just assembling some interesting “facts” for my files, so this could be boring. You won’t offend me much if you stop reading now.

This paper is from the University Medical Center Groningen and Human Origins Group (Faculty of Archaeology, Leiden University), both in The Netherlands. It’s 23 pages long, not counting the 450 references.

I’ll following the spelling conventions of the paper’s publisher.

Introduction

“…our genome has remained basically unchanged since the beginning of the Palaeolithic era.”

“Since the onset of the Agricultural Revolution, some 10 thousand years ago, and notably in the last 200 years following the start of the Industrial Revolution, humans have markedly changed their dietary habits. Consequently, it has been advocated that the current pandemic of diseases of civilization results in part from the mismatch between the current diet and our Palaeolithic genome.”

These are some of the diseases that may result from the mismatch of our Palaeolithic genome and modern lifestyle (including diet): type 2 diabetes, high blood pressure, osteoporosis, fertility problems (polycystic ovary syndrome), pregnancy complications (pre-eclampsia, gestational diabetes), some cancers (colon, breast, prostate), heart disease (such as coronary artery disease), major and postpartum depression, autism, schizophrenia, some neurodegenerative diseases (Parkinsons disease, Alzheimer’s disease). [Sorry, Dr. Cordain – no mention of acne. And I wonder about dental and eye problems.]

Evolutionary Medicine

“Many, if not all, diseases can become explained [sic] by both proximate and ultimate explanations. The science searching for the late explanations has become known as ‘evolutionary medicine.’ Unfortunately, modern medicine deals mostly with proximate explanations, while ultimate explanations seem more prudent targets for long-time disease prevention.”

The term “evolutionary medicine” was coined by Randolph M. Nesse and George C. Williams in the early 1990s. It’s also called Darwinian medicine.

“…about 20% of modern hunter-gatherers reach at least the age of 60 years.”

After the transition to the Agricultural Revolution about 10,000 years ago, life expectancy fell from about 40 years to about 20 years. This is astounding news to me, assuming it’s accurate.  (Remember that for most of human existence, infant and child mortality has been very high. If an infant dies at 6 months old and an adult dies at 40 years, average life expectancy for the two would be about 20 years.)

Average life expectancy among modern hunter-gatherers is about 40 years—same as it was for students of the Harvard College class born in 1880.

Life expectancy in the Neolithic era was stable until the late 18th century, rarely exceeding 25 years in civilized nations.  At that point, life expectancy started to improve dramatically thanks to sanitation, water and food hygiene, immunizations, and quarantine practices. (Thomas Jefferson was the third president of the U.S.  His wife Martha had six children but only two survived to adulthood.)

The earliest species in the genus Homo appeared about  two million years ago.   Homo sapiens appeared about 200,000 years ago in south or east Africa. Several different hominin lines co-existed with modern humans.

The current world population of humans may be derived for only 1000 or so individuals that survived a decimating event.

The ability to store fat is one of the things that differentiate us from other primates.

Hunting and Our Ancient Diet

The composition of the early human diet is still hotly debated.

Lotta work to snag one of these

In modern hunter-gatherers, only about 30% of diet energy is derived from hunting, with the rest coming from gathering plant food and aquatic animals.

In contrast to the arid, hot, iconic savanna, “…the combined evidence strongly suggests that early hominins frequented the land-water ecosystem and thus lived there.” If rainfall and other conditions allowed, there would be wooded grasslands.

“…the proportion of the human gut dominated by the small intestine (>56%) suggests adaptation to a diet that is highly digestible, indicating a closer structural analogy with carnivores than to [animals that eat leaves and fruit].”

“The data of combined studies of early hominins and the more recent hominins suggest a gradual increase in dietary animal protein, a part of which may derive from aquatic resources. In the more recent human ancestors, a substantial part of the dietary protein was irrefutably derived from marine resources, and this habit was only abandoned in some cases after the introduction of agriculture at the onset of the Neolithic.”

Sea levels have risen over the past 17,000 years, up to 150 meters.

“In conclusion, there is ample archeological evidence for a shift from the consumption of plant towards animal foods.”

“For a long time period in hominin evolution, hominins derived large amounts of energy from (terrestrial and aquatic) animal fat and protein. This habit became reversed only by the onset of the Neolithic Revolution in the Middle East starting about 10,000 years ago.”

“The Homo genus has been on earth for at least 2.4 million years and for over 99% of this period has lived as hunter-gatherers.”

“We conclude that gathering plays, and most likely always played, the major role in food procurement of humans. Although hunting doubtlessly leaves the most prominent signature in the archaeological record, gathering of vegetables and the collection of animal, notably aquatic, resources (regardless of whether their collection is considered as either hunting or gathering), seems much easier compared with hunting on the hot and arid savanna. We suggest that it seems fair to consider these types of foods as an important part of the human diet, unless proven otherwise. Conversely, while hunting might have played a much more important role at higher latitudes, dietary resources in these ecosystems are rich in n-3-fatty acids (for example, fatty fish and large aquatic mammals), while the hominin invasion of these biomes occurred only after the development of more developed hunting skills.”

Even though traditional Maasai showed extensive atherosclerosis with fibrous changes and lipid infiltration, they had very few complicated arterial lesions and rarely had clinical cardiovascular disease events.

The Agricultural and Industrial Revolutions

“Contrary to earlier belief, the advent of agriculture coincided with an overall decline in nutrition and general health, but at the same time provided an evolutionary advantage since it increased birth rates and thereby promoted net population growth.”  [Both supporting references are from CS Larsen.]

Good news for birth rates

With the advent of the Industrial Revolution, nutritional quality and general health declined even more rapidly.

“Among the many dietary and lifestyle changes are: a grossly decreased n-3:n-6 fatty acid ratio, the combined high intakes of saturated fatty acids and carbohydrates, the introduction of industrially produced trans-fatty acids, reduced intakes of n-3 and n-6 long-chain polyunsaturated fatty acids, reduced exposure to sunlight, low intakes of vitamins D and K, disbalanced anti-oxidant status and high intakes of carbohydrates with high glycaemic indices and loads, such as sucrose and industrially produced high-fructose maize syrup.”  [Aren’t we eating more n-6 fatty acids, not less?]

Potential Benefits of a Palaeolithic Diet

The authors conclude with a review of the few medical scientific studies of Palaeolithic diets in modern humans. These are the ones by Frassetto, Osterdahl, Jönsson, and Lindeberg. I’ve already reviewed those here.  They missed O’Dea and Kerin’s study.

My Overall Impressions

This article seems very well researched.  It lays out a logical framework for the discipline of evolutionary medicine and should spur further clinical research.  It’s well worth a read if you have more than a passing interest in paleo lifestyle theory.

Bear in mind I’m not a paleontologist, anthropologist, paleo-anthropologist, or archeologist.  So caveat lector.

Steve Parker, M.D.  (B.S. degree in zoology)

Reference: Kuipers,RS; Joordens, JCA; and Muskiet, FAJ. A multidisciplinary reconstitution of Palaeolithic nutrition that holds promise for the prevention and treatment of diseases of civilization. Nutrition Research Reviews, 25 (2012): 96-129.  doi: 10.1017/S0954422412000017

PS: The Paleolithic diet is also called paleo, ancestral, hunter-gatherer, Stone Age,  Old Stone Age, and caveman diet.