Dear EarthTalk: How is it that some food purveyors are contributing to the destruction of tropical rainforests by ditching unhealthy “trans fats?” — Billy S., Salem, OR

Most public health advocates applaud efforts by processed food producers, restaurants and fast food chains to get rid of so-called “trans fats”—partially hydrogenated oils added to foods to improve texture and extend shelf life but which can aggravate heart disease. In 2013 the U.S. Food & Drug Administration (FDA) proposed eliminating trans fats altogether, but it is unclear if and when such a change will take effect. In anticipation, many big trans fat buyers have switched to palm oil, much of which comes from former tropical rainforest lands cleared for agricultural production across Southeast Asia.

“The concern is that a lot of companies will switch to palm oil in order to reduce trans fats without thinking more broadly about the health and …