08/12/2012 (Mongabay.com) -  Animal fats and margarine consumption in the United States have been largely replaced by palm oil, a plant-based oil that has similar cooking properties, but may not be as environmentally-friendly as commonly believed, argues a researcher in this week's issue of Nature.

José Bonner, a biologist at Indiana University, analyzed fat consumption trends in the United States and compared the chemical make-up of palm oil, lard, and margarine. He finds that chemically, the three are near substitutes for one another. Accordingly, health fads and the rise in cheap palm oil has led to it replacing margarine, which originally supplanted lard, when it fell out of fashion due to health concerns.

"The popularity of butter and lard declined in the 1940s and 1950s, giving way to margarine. This shift was fueled by the belief that vascular health could be improved by switching from saturated animal fats to unsaturated plant oils. Margarine fell from grace around 1990, when it was discovered that plant-oil solidification produces metabolically harmful trans-fat," he writes. "The physical-chemical properties of lard make it ideal for baking, and palm oil is an effective substitute because its chemical composition is almost identical."

Bonner: "In lard, the ratios of saturated, monounsaturated and polyunsaturated fatty acids are 43:47:10, whereas in palm oil they are
47:45:8. Neither type contains significant amounts of the more beneficial omega-3 fatty acids." Fatty acid abbreviations: C14 = myristic;
C16 = palmitic; C17 = margaric; C18 = stearic; C20 = arachidic; C16:1 = palmitoleic; C18:1 = oleic; C18:2 = linoleic; C18:3 = linolenic;
C20:1 = gadoleic. Courtesy of José Bonner.

The problem, says Bonner, is palm oil is neither as healthy or environmentally-friendly as some believe. Over the past 20 years large swathes of rainforest across Malaysia and Indonesia have been cleared for oil palm plantations. The industry is now expanding in other parts of Asia, Central and South America, West and Central Africa, and even Madagascar.

"Vegetarians may welcome this plant-based lard as being animal-friendly, but it is hardly so if it destroys the habitats of countless animals, from endangered lemurs and orangutans to the Mauritius Kestrel," Bonner told mongabay.com.

"Destruction of tropical rainforest to create oil palm plantations is bad enough in terms of biodiversity reduction and species extinction. To add also the significant increase in CO2 emissions [from forest and peatlands conversion] makes it even worse. And to what end?"

Palm oil has the highest yield of any of the major oilseeds. Accordingly the industry argues it
requires less land than other crops to produce a given amount of oil. But producers have been
challenged by environmentalists who note that oil palm expansion tends to occur at the expense
of carbon-dense and wildlife-rich rainforests and peatlands, generating substantial environmental
impacts. In response to these concerns, a variety of stakeholders in 2004 formed the Roundtable
on Sustainable Palm Oil (RSPO), which sets basic standards for palm oil production, with the aim
of reducing its environmental impact as well as adverse social outcomes.

Bonner suggests that American consumers might be better off going back to lard, especially when it's already a byproduct of livestock production, which itself has a substantial global footprint.

"So we have come full circle," he said. "The intense drive to avoid lard has led us, in the end, right back to lard. Why discard the pork fat from our abbatoirs only to replace it with the same thing, but from an ecologically-disastrous source? Let’s just use the lard."

Trends in U.S. Fat Consumption. From Data and Statistics tables, USDA. Courtesy of José Bonner.