(Donna McWilliam/Associated Press)

You may have thought it was just a quick, convenient and perhaps not-so-healthy bite to eat. But it turns out that a hamburger and fries is also an ideal representation of a phylogenetically diverse diet.

That's a scientific way of saying that it contains a lot of different plant material sourced from all over the globe.

People throughout human history have traditionally had a fairly limited diet, phylogenetically speaking, because they relied mainly on what could be foraged or grown locally. But suddenly, when framed in terms of the evolutionary development of human beings, the globalized economy has changed all that.

Researchers at the University of Calgary have conducted a unique study of the plants around the world that people now use as food, the first study of the "phylogenetic distribution" of the modern human diet. The study, called Plant Diversity in the Human Diet: Weak Phylogenetic Signal Indicates Breadth, used a common meal available in many parts of the world — a McDonald's Big Mac, french fries and a cup of coffee — as a case study of what people eat these days and where it comes from.

"Generally speaking, we eat very broadly from the tree of life," says U of C plant evolutionary ecologist Jana Vamosi. "Others have looked at the sheer number of plant species we consume, but nobody has ever examined whether the plants we eat are clustered in certain branches [of genetic groups]. It turns out that they are not."

Vamosi worked with a team of researchers led by Serban Proches from Stellenbosch University in South Africa. They examined more than 7,000 plant species that people are known to eat to examine the origins and evolutionary relationships of the various plants that comprise the human diet.

The researchers found that we modern humans are likely the only creatures on the planet who consume such a broad spectrum of plant species. This dietary diversity is the result of a number of factors, including the vast geography we inhabit, our sophisticated international trade systems, our seemingly endless appetite for new foods, plus our bodies' ability to process all sorts of different foods.

"Humans are generalist feeders in the broadest sense," the study says.

Diversity at root of modern food supply

All this, the researchers say, has led to food becoming the ultimate symbol of a globalized society.

Take that Big Mac and fries chased with a cup of coffee. This seemingly simple meal actually has complex origins, containing about 20 different ingredients and plant species drawn from sources all over the world. The potatoes were originally domesticated in South America, for example, and the mustard was developed in India. The onions and wheat originated in the Middle East, the coffee in Ethopia.

That's a pretty impressive list when combined in a single meal, says Vamosi. "Some human societies — those that are largely unaffected by current globalization trends — commonly include only 50 to 100 plant species in their entire diet," she says.

But while our mothers have been telling us forever that we're supposed to eat lots of different fruits and vegetables, someone might want to mention to mom that just eating lots of different types of produce may not be boosting our nutrition significantly. The truth is that many of the plants that have become common sights on grocery shelves actually share common genetic roots as well.

"Eating carrots and celery, for example, provides you with nutrients from the same plant family as do apples, pears, apricots, peaches, raspberries and blackberries. Indeed broccoli, kale and cauliflower are actually a single species," Vamosi says.

So while globalization has added new plants to the food supply, it actually takes a little research if you want a truly diverse mix of plants in your diet.

"Eating lots of different produce might not actually provide you with a phylogenetically diverse diet," Vamosi says. But, she adds, "Whether that's important for providing maximum nutritional value remains to be seen."

That's because there's been little analysis so far of the nutritional content of a diverse versus a narrow diet. More research is needed now to see whether eating a phylogenetically diverse diet is better for us than consuming a more limited range of foods.

The downside of globalization

We may be enjoying a more diverse diet as individuals today, but as a species, we may simultaneously be moving in the direction of a more uniform diet because everyone is preferring the same processed foods. The study — which was published in the February 2008 issue of the scientific journal BioScience — suggests more research is needed to investigate whether we need to work toward protecting some of the plant species that we are not eating.

As globalization and industrial-scale agriculture increase, plants native to a region are often cleared to make way for the cultivation of more popular food plants. The study says we may be at risk of losing some species that don't make it into that burger and fries, which could lead to problems for the food supply in the future.

"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," Vamosi says. "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 into the future."

Vamosi adds that it's also still unclear whether the globalization of our diet makes our food supply more, or less, secure.

"The reason why it may be less secure is simply because people are growing crops that originated elsewhere, and they may be more prone to crop failure," she says. "It's really hard to foresee all the benefits or costs of globalization of food supply."

Vamosi adds that there are a number of other questions raised in this study about nutrition and diversity of the human diet that could be tackled through research. In fact, the study argues that: "Cross-cultural analyses of diversity in the plant diet of humans could represent a fascinating new field of research linking ecology, anthropology, history, and sociology."

So the next time you bite into a Big Mac, remember you're doing more than feasting on dozens of different plant species from all over the world. You could also be biting into an interesting new field of research that asks whether globalization of our diet is good for us.

[an error occurred while processing this directive]