Saturday, June 09, 2007

Ecological Footprint of Food Items

Andrea Collins and Ruth Fairchild have released an interesting report: Sustainable Food Consumption at a Sub-national Level: An Ecological Footprint, Nutritional and Economic Analysis. It looks at impact of our diets on our ecological footprint and what changes can be made in our diets to reduce it.

According to the report, diet is responsible for around 1/4 of the total ecological footprint of individuals. Surprisingly, the transportation of food has a very small impact (1.7%) on the overall footprint.

The part I found most interesting was the table that listed the ecological footprints (in global hectares or gha) for various food items. The footprint was calculated by kg, but I think it is also helpful to look at it by calorie (kcal), so I calculated those values.

Itemgha /
1000 kg
gha /
kcal / kg
Meat Products
Milk Products
Whole Milk1.42.3600
Vegetable Products
Vegetable Oil3.80.48840
Soft Drinks0.20.5400

Take Aways

1) Instead of focusing on how far the food travels, the packaging that food comes in, and whether the waste is recyclable, you can make a bigger positive impact on the environment by focusing on what you are eating. Eating rice and beans that were farmed in Bangladesh using conventional means and shipped in a non-recyclable plastic container is better for the Earth then eating a organic locally grown steak that was that was packaged in a bio-degradable plastic.

In the report they show how making a few substitutions from high to low footprint foods (cheese to eggs, beef to pork, fish to cereals, and spirits to beer) can reduce an individual's footprint by 20%.

2) Like the other numbers that I have looked at the best way to minimize your ecological footprint is to replace meat and animal products with vegetable products. A low calorie vegan diet has the smallest footprint.

3) Vegetarians that substitute cheese and other milk products for meat do not lower their ecological footprint much and might in fact raise it. As was the case in a previous study, eating chicken has a lower ecological footprint per calorie than cheese does. Pork also comes in lower than milk products, which is surprising to me and doesn't jive with other numbers I have seen.

4) Sugar has the lowest footprint by calorie, but I am ambivalent on recommending it, for it lacks micro-nutrients and fiber.

5) Vegetables and fruits have similar footprints to eggs, chicken and pork by calorie. But, this is misleading as fruits and vegetables are not eaten just for their calories but also for their fiber, vitamins and other micro-nutrients. These numbers are also just an average for all fruits and vegetables, and specific items will vary greatly depending on the caloric content. Some examples of calories per kg: carrots 333, beans 310, peas 806, apples 520, bananas 888 and oranges 472.

6) Some day I hope to have the ability through either a website or a Quicken like piece of software to track the ecological impact of my diet. This data is getting close to what is needed to make that happen. It goes along with the numbers I have previously collected on CO2 footprints and land footprints of food.

While I like the ecological footprint, I wish they broke out the energy usage and land use rather than converting them into one number. I have written previously on why I don't think energy should be part of the ecological footprint, and if this were broken out I could finally have the acres and gallons numbers that I am looking for.

1) This is from a study in Cardiff, UK. I don't know how well the numbers would hold for the US, but I bet they would be similar.

2) I don't know where the numbers in this study originally came from and what the underlying assumptions were. While I would guess it includes the energy use to create the fertilizer and run the tractors, I am not sure if it handles the energy to transport, refrigerate, cook the food and handle the garbage.

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