Is lettuce worse than bacon?

You might have seen headlines in the last few weeks saying something to the effect that lettuce is worse than bacon in terms of greenhouse gas emissions. This may have caused a slightly surprised raise of your eyebrow as you will also probably be aware of previous studies affirming that vegetables are lower in greenhouse emissions than meat. So what is going on here? The answer is that often the facts aren’t allowed to get in the way of a good headline.

The recent study involved researchers examining how growing, processing, and transporting food, food sales and service, and household storage impacts resource usage like energy use, water, and greenhouse gas emissions. One of the reported conclusions was that eating lettuce leads to three times more greenhouse gas emissions than eating bacon, yet this doesn’t sit comfortably with lots of other studies.

The comparison of lettuce to bacon would only hold true if you assume that any person would replace a protein source with a mostly water-laden vegetable by weight.

To quote just one other study from the University of Lancaster (published in the journal Energy Policy if everybody swapped their current eating habits to a vegetarian or vegan diet then greenhouse gas emissions would be cut by 22 to 26 per cent. There is a lot of research showing that vegetable consumption is better for the planet than meat consumption so what is going on with this latest study?

For an excellent critique of the reporting on the study you can go to an article by Dan Nosowitz at www.modernfarmer.com but here is the gist of what it says. For a start the headlines reporting lettuce being worse than bacon came from a press release, not the study itself. The study was actually titled, “Energy use, blue water footprint, and greenhouse gas emissions for current food consumption patterns and dietary recommendations in the US”. Nosowitz spoke to the study authors who were not too pleased with the spin put on the article by the publicity folk.

As Nosowitz points out the comparison of lettuce to bacon would only hold true if you assume that any person would replace a protein source with a mostly water-laden vegetable by weight. The Nosowitz article also questions the assumptions made about pork production and points out that the data provided on lettuce only applies to lettuce grown in California.

The real essence of the original study was that not all fruits and vegetables are good for the environment and not all meats are bad. The weight of scientific evidence seems to be that a largely vegetarian diet is better for the planet than a largely meat-based one however, as this study points out within the vegetable choices available some are better than others. The headlines re “lettuce vs bacon” were probably intended to provide solace to people wanting to hold onto their meaty diet, but the evidence really is that for the future we need to limit meat consumption and increase vegetable and fruit intake. The other lesson of course, is read beyond the headline.