by Marion Nestle
Jan 11 2008

What’s the deal on saturated fat?

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.

  • I say stick with pastured animals for meat and dairy and don’t worry too much about saturated fat. In my opinion, high levels of saturated fat is a byproduct of CAFO’s

  • Anton

    Somewhat helpful. But I think it might be unfair to blame ‘journalists’ for harping on single nutrients, or for repeating the ‘artery-clogging saturated’ fat meme.

    One VERY LOUD message from the RD and nutrition community for maybe 20 years now is LOW-FAT. CUT THE FAT. CUT THE MEAT. The popular media are full of RDs who harp about ‘fatandcalories’ and ‘leanmeatsandfish’ and ‘lowfatmilkandyogurt’ and ‘healthyeating=lowfat”.

    You have RDs and nutritionists on the Today show saying “full of cancer-fighting antioxidants”, or “this muffin has 42 grams of fat.”

    You have magazines — with RDs on staff an advisory boards –like Cooking Light predicated on the very notion of eating less fat.

    It’s also the FIRST line of any weight-loss advice. “The best way to reduce calories is to REDUCE THE FAT, nine calories a gram . . . etc.

    Even the scientific research community DESIGNS its research around trying to ‘prove’ how fat bad is.

    The nutrition community was the one that started the single-nutrient business and the fat-is-bad message, not journalists.

    In that, the community succeeded. And, in my estimation, it was all on pretty flimsy evidence.

  • Amanda

    Marion I was wondering what your opinion is of the work of Weston A. Price and his theories on the value of fats in the diet of primitive peoples?

    I have followed many of the principles outlined by the Weston Price Foundation and found them to be helpful with regard to health issues like allergies and even weight control. They argue that heart disease increased exponentially after the introduction of margarines and other polyunsaturates on a large scale into the modern diet, and that saturated fats like good quality butter, whole milk and animal fats do not contribute to heart disease. They also argue that cholesterol is actually protective and that the reason it is found at the site of most heart attacks is that it is actually one of the body’s ways of repairing itself. Cholesterol has been blamed as the cause of heart disease and cardiac arrests because it is at the scene of the crime rather than because it is guilty.

    But I still wonder what the truth is about fats and cholesterol – it is very confusing.

  • As I keep saying, the science is complicated, especially when studies examine fats of one kind or another outside of their dietary context. Whether fats are good, bad, or indifferent may depend on everything else you are eating, and even more importantly, how much. Intelligent people can disagree about interpretation of the science, but I am impressed that everyone agrees it is better to eat whole than processed foods in amounts that balance energy intake and expenditure. If you do that, you really don’t have to worry about the nutritional details.

  • rj

    It seems it is more of a case of the quantity of saturated fat than the single nutrient itself being terrible. Much like high-fructose corn syrup. And so the advice on moderation being apt.

    About whole foods and processed foods, are there many studies outlining the degree of stress that the liver undergoes with respect to heavily processed foods? Where heavily can be defined as consisting of 30 to 40 different food additives?
    e.g., think of a twinkie or even some brands of bread.

  • In the same vein as Anton’s comment, I think it’s ironic that all the experts tout whole foods … until we start talking about foods that come from animals. Then it’s suddenly, trim the fat from your steak, peel the skin off your chicken, don’t eat the organ meats because they’re high in cholesterol, throw out every other egg yolk, and drink skim milk and reduced fat cheeses instead of their whole counterparts.

    Are we supposed to eat whole foods or aren’t we? Personally, I say yes.

  • Fentry

    Migraineur’s comment is quite prescient. Although I too tout “organic,” I always like to point out that hemlock is organic too–that doesn’t make it more healthful.

    Men’s Health assumed that one never remembers a previous month of Men’s Health. Otherwise, they would not have to tell men how to attract women in every issue. As a Men’s Health subscriber for too many years, they routinely publish two-sentence blurbs on all manner of health studies.

    The reader is never treated to methodology, to context, to an explanation or even to a reference where he can get one. If one does read and remember from issue to issue, you’ll find that the sentence-long tips derived from these studies often conflict.

  • Fentry

    As Amanda says, heart disease may be on the rise, and perhaps the Weston Price Foundation is one to it.

    I would like to point out though that my great-grandfather died in his 40’s of pneumonia. Men in my family who have lived past 50 tend to die or heart disease; the few who live past 70 tend to die of cancer.

    It may be that whether heart disease is on the rise–or cancer–or something else–is an artefact of mortality statistics. After all, we have fewer people dying of diphtheria, measles, malaria, etc.

  • Amanda

    I think that might be true about the changes in demographics over the past generation. Also, people worked physically harder 100 years ago than they do now – maybe as our lives became more sedentary, our arteries became more clogged!

    I also read that once you take the fat out of milk, it is difficult to absorb the calcium from it. Marion, can you state whether this is true?

    With regard to fat, I find reducing sugar to be more helpful in controlling weight rather than fat. I lost 18 kg (roughly 40 pounds, a bit less…not sure of the exact conversion) by giving up sugar – as Marion said in her book, its about the calories you eat. I was getting a lot of calories from sugar – so I just cut out the sugar totally and started exercising. For me a life without butter and olive oil and skin on my chicken doesn’t cut it. But I can and do live without the sugar – although I do slip up occasionally and have to get back on the wagon. The first three weeks without sugar were pure HELL – after that I was fine. And I didn’t think I ate that much sugar…but I was wrong. 40 pounds wrong!

  • Carri

    I too agree with the Wesston Price Foundation. The book Nourishing Traditions by Sally Fallon (who is the current president of the foundation) makes sense to my world view. God gave us food to eat in the natural unprocessed form and it was man who got his little hands in it and messed it up. I also read that taking the fat out of milk interferes with the absorption of calcium. When you think logically about all this, when we make things low fat or fat free, we are de-naturing our food. This isn’t it’s natural state. And that logic applies across the board for all our foods. Maybe the key is a proper balance of the right whole foods.

  • Weston Price advice has much to recommend, but calcium is water-soluble. If anything, fat interferes with its absorption (although not by enough to worry about).