When Wendell Berry first wrote "Eating is an agricultural act" in 1989, the majority of people in Australia were so disconnected from their food supply that their children believed machines made milk and that spaghetti grew on trees. More than two decades later our collective understanding of where food comes from and how it is produced has not improved.

So what does eating is an agricultural act really mean? At its most basic it reasserts the direct link between the food we eat, and the agriculture that produces that food. When we choose to eat something, this simple act sets off a chain of events that can be traced all the way back to the farmers decision what to plant and harvest. This is simply demand driven supply.

For those so inclined the formula for most of humanity looks like this: A = E (agriculture (A) = food (F) = eating (E), so A=E). The reverse, E=A, is also true because if we don't eat, no one will bother to grow and process the food (agriculture) for us, and the equation must balance.

With the basics out of the way it starts to get interesting when we say things like, "saving the planet, one meal at a time". If demand stimulates supply it means that when the demand changes so will supply. If you and your family love apples and eat lots of them, the grocery store owner will order more of them and this sends a signal to the farmer that perhaps she should plant more apple trees. However this could mean she needs to clear more land to expand the orchard, which in turn means a loss of natural habitat. This simple example links food with ecology and the environment via the many billions of eating decisions made by each of us every day. This means we can confidently say "eating is an ecological act and that our food choices determine the fate of our planet".

Perhaps that was too strong a statement? Maybe, but the statistics say it is accurate. In Australia roughly 17% of all carbon emissions are attributed to agriculture, but agriculture is only one part of the process that gets food to your table. The food you chose to eat usually involves; land clearing, agriculture, transport to processor, processing, packaging, transport to wholesaler or distribution center, storage, more handling before transporting to retail outlet, more transport to get it to your home, storage, cooking, cleaning and waste. So food is a system or chain, and often each step in the chain is refrigerated which means greater energy use and emissions.

Obviously all this handling, which happens after the agricultural phase, uses energy, and vast amounts of it, to the point where food embodies more energy and generates more carbon emissions than any other sector of our economy. Food crosses so many sectors that the figures are a bit rubbery, but estimates are that food in Australia accounts for up to 40% of our total carbon emissions.

So eating is most definitely a significant ecological and environmental act, and unless you own an aluminium smelter, the most significant thing you can do to save the planet is to choose what you eat with this in mind. If you change what you eat, you can change where it comes from, how it is grown, who grows it, who distributes it, who sells it, how it is processed: in fact, you have total control of the system through your food choices. Now that is empowering.