If you eliminate oils with trans fats, you have to replace them with fats with equivalent levels of saturation, and palm oils are highly saturated and work well as substitutes. One consequence of the increased demand for palm oils is destruction of tropical rainforests. “To improve the industry’s image and avert a consumer backlash,” food companies are pushing palm oil producers to go green and promise to produce palm oils sustainably. Will this work? It will be interesting to see.

In the meantime, the New York Times has plenty to say about how using palm oil for fuel drives up the cost of food.

A reader, “rj,” sends a link to an article in Men’s Health (”What if bad fat isn’t so bad”), and asks about: “The supposed inconclusive evidence for sat fat being the culprit in atherosclerosis. Personally, I couldn’t find any credentials of the author but nevertheless would be much interested in your thoughts on the matter.”

My thoughts: As I keep saying, nutrition science is complicated and this article, by an excellent science journalist, is the latest in a series by excellent science journalists (see, for example, the recent books by Gary Taubes and Michael Pollan) to point out the inconsistencies in data on saturated fat and heart disease risk. Let me make several quick points: (1) All fats–no exceptions–are mixtures of saturated, unsaturated, and polyunsaturated fatty acids (2) Saturated fats occur in greater proportions in animal fats–meat and dairy foods, (3) Some epidemiologic evidence–but not all–suggests that people who eat a lot of meat and dairy foods have a higher risk of heart disease than people who eat a lot of fruit and vegetables (this is correlation, not causation), (4) The same clinical studies that show how trans fats do bad things to blood cholesterol levels also show that saturated fat does too, although not as much (But: people take in a lot more saturated fat than trans fat), and (5) Saturated fat is a single nutrient and the studies reviewed and discussed by the journalists take saturated fat out of its dietary context.

Out-of-context studies of single nutrients are exceedingly difficult to interpret. At the moment, today’s dietary (not single nutrient) advice is the same as it has been for the last fifty years. As I put it in What to Eat, “Eat less, move more, eat plenty of fruits and vegetables, and don’t eat too much junk food.” Michael Pollan gives exactly the same advice: “Eat food. Not too much. Mostly plants.” Do this, and you really don’t need to give a thought to single nutrients.

I discuss the politics of diet and disease recommendations in my book, Food Politics (now out in a new, expanded edition), and this particular question in “Ask Marion” on Eating Liberally.

Does this help at all? Thanks for asking.

Here’s a quick question, just in: “I finally got the chance to finish What to Eat, and I noticed that you didn’t talk about non-hydrogenated margarine in your margarine section. I’m not wondering if it’s better for you because I’m sure it’s still soybean oil with a bunch of stabilizers, but I’m just wondering how it’s made.”

Response: I did actually, but in two other chapters, the next one and the one on fats and oils so the explanation is hard to find. Sorry about that. Here’s the deal: companies use variations of two methods: (1) substitute a highly saturated fat like palm kernal or coconut oils, or (2) mix a totally saturated fat (which will not have any trans) with an unhydrogenated fat (also trans-free) until you get the degree of thickness required. Both methods increase the amount of saturated fatty acids. Saturated fats raise the risk of heart disease, but not as much as trans. So the substitutes are likely to be marginally better than oils with trans.

I have long talked about trans fat as a calorie distracter. People think “trans fat-free” means “calorie-free” when it most definitely does not. Whatever replaces trans fats will have just as many calories–130 per tablespoon, meaning that each tablespoon is 5% of a day’s average calorie intake. That’s why I either laugh or cry when I see “zero grams trans fat”
on the labels of junk foods. Trans fats raise the risk of heart disease a bit more than do the saturated fats that occur naturally in foods. But trans fats are unnatural and unnecessary and it’s good to get rid of them. Yesterday’s Wall Street Journal explains how food companies are struggling to find replacements that do not increase the amount of saturated fat in processed foods. This, as it turns out, is not so easy to do. I discuss all this in the fats-and-oils chapter of What to Eat, so I’m happy to see the WSJ take it on.