The reasons, according to the authors of the new book Evolving Human Nutrition: Implications for Public Health, can be traced back to our pre-human and early homo sapiens, caveman diet.
Nutritional biochemist, Professor Neil Mann, Head of Food Science in the School of Applied Sciences at RMIT University, is a co-author of the book, along with anthropologists Professor Stanley Ulijaszek from Oxford University and Dr Sarah Elton from The Hull York Medical School.
The book, primarily aimed at postgraduate anthropology students, looks at how food helped us evolve from apes into human hunter-gatherers and how the relatively recent switch to farming and food processing have impacted negatively on our physiological and biochemical adaptations brought about by this evolution.
Food’s role in creating civilisations and how our manipulation and selective breeding of foodstuffs and basic ingredients, which still affects us today, are also covered.
“The changes made to our food intake by changing from hunter-gathering to farming then later changes to food composition during the industrial revolution 250 years ago, when food production became more mechanised, dramatically altered the food we eat, but our bodies have not evolved to cope with those changes,” Professor Mann said.
“I tell my students, they shouldn’t feel bad about craving fat and sugar, as those sweet and greasy tastes were the signs to our caveman ancestors that a food was safe to eat and would provide needed energy, something often lacking in their world.
“The problem is our western diet has an over-supply of these desirable components.”
While a broad diet of scavenged or hunted meat and foraged plants helped our ancestors develop into the big-brained, bipedal people we are today, it is only relatively recently, in the last 10,000 years or so, that we have started growing and harvesting grains and eating dairy.
“Once wild game became scarce, people started selecting and growing grains, such as wheat, oats and barley in the Middle East, and rice in Asia, from native wild grasses,” Professor Mann said.
“Agriculture was the start of civilisation, and allowed people to settle into permanent communities, diversify their roles from just being hunter-gatherers, and become craftsmen, architects, doctors etc.
“But the down side was poor health, as humans are not well designed to live on a narrow grain dominated diet.
“We know from the archaeological record that when civilisations sprang up, these early farmers had reduced life expectancy, and were not particularly healthy, suffering many deficiency diseases,” he said.
Professor Mann said the four years’ work on the book involved trips to Oxford, working in the School of Anthropology, examining many scientific studies of both fossil remains and data on current hunter-gatherer groups around the world. The book covers the findings of more than 2,000 studies and research papers.
Evolving Human Nutrition: Implications for Public Health is available from Cambridge University Press as part of the Cambridge Studies in Biological and Evolutionary Anthropology series. It is on sale in Australia this month. It costs $130 and can be ordered online.
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