Big Mac serves up the whole world on one plate

Engela Duvenhage

Fast food meal dissected in new study of globalization and diversity of the human diet

A Big Mac and fries may be the quintessential fast food meal, but it can also be viewed as the perfect example of humanity's increasingly globalised diet as it contains over 20 plant species from around the world, according to Stellenbosch University researchers who have conducted a unique study of all the plants that people eat worldwide.

In the first-ever study of the "phylogenetic distribution" to show the ancestral relationship of the human diet, a team from the DST-NRF Centre for Invasion Biology at Stellenbosch University, ecologists Dr Serban Proches, Dr John Wilson and Prof Dave Richardson collaborated with plant evolutionary ecologist Dr Jana Vamosi from the University of Calgary in Canada. Their findings were published in the February issue of the journal BioScience (the journal of the American Institute of Biological Sciences).

They found that humans, compared to other species, seem to be in a class of their own when it comes to the range of plant species consumed. Our ability to process food combined with an insatiable hunger for new tastes and international trade systems has also led to food becoming the ultimate product of a globalized society.

"You could say that we eat very widely from the tree of life," says Dr Wilson, a postdoctoral associate of the CIB, a centre that studies the movement of species across the globe and how it affects indigenous plants and animals. "Others have looked at the sheer number of plant species we consume but nobody has ever examined whether we tend to eat only particular types of species from particular families. It turns out we do not."

The researchers examined more than 7,000 plant species eaten by people to determine the origins and evolutionary relationships of the various plants that comprise humankind's menu. In addition to confirming the incredible number of species that are regularly eaten, they found that we chow down on members of a remarkably high number of plant families.

As a case study, the scientists analyzed the ingredients of a simple fast food meal - a McDonald's Big Mac with French fries and a cup of coffee - to illustrate the extent of our globalised diet. From potatoes that were first domesticated in South America, to mustard that was developed in India, onions and wheat that originated in the Middle East and coffee from Ethiopia, they found the meal contained approximately 20 different species that originate from all around the world.

The researchers believe that "a Big Mac is an apt symbol of globalization". "There are only eight places in the world where most plant species were domesticated. A burger, fries and coffee contains species from all these regions," says Dr Wilson. "The Big Mac is a combination of years of plant breeding from many different civilisations around the world."

"That a single meal contains about 20 species is impressive, given that some human societies-those that are largely unaffected by current globalization trend-commonly include only 50 to 100 plant species in their entire diet," the paper states.

The study raises myriad questions about the diversity and nutritional aspects of the human diet that will be the subject of future investigations. The study also argues that steps to protect the diversity of human food plants may have to be taken as loss of indigenous knowledge gradually leads to more uniform diets for the world's population overall.

"Individually we are probably eating a greater range of plant species than our ancestors, but the loss of regional cuisine and indigenous knowledge of, for instance, the Nama on what local Northern Cape plants are potentially sources of food, may mean that as a species our diet is becoming increasing focussed on a few plant species, and indeed a few varieties of those species," Dr Wilson argues.

"The fact that we do eat so broadly indicates that we enjoy many different flavours and combinations of flavours and also indicates that many plants that we don't eat likely have some sort of culinary value that we just haven't discovered yet," Dr Wilson said. "Maintaining plant diversity ensures that we will continue to have the current flavours that we enjoy available to us and will also preserve other potential food sources that we haven't even discovered yet."

Note: * The paper "Plant Diversity in the Human Diet: Weak Phylogenetic Signal Indicates Breadth" by Dr Serban Proches, Dr John R. U. Wilson, Dr Jana C. Vamosi and Prof Dave Richardson is published in the February 2008 issue of the journal BioScience http://www.aibs.org/bioscience/index.html

February 2008