The low-fat trend finally appears to be on its way out. The notion that saturated fats are detrimental to our health is deeply embedded in our Zeitgeist--but shockingly, the opposite just might be true. For over 50 years the medical establishment, public health officials, nutritionists, and dietitians have been telling the American people to eat a low-fat diet, and in particular, to avoid saturated fats. Only recently, have nutrition experts begun to encourage people to eat "healthy fats."
This past December, the Los Angeles Times reported that excess carbohydrates and sugar, not fat, are responsible for America's obesity and diabetes epidemics. One of the lead researchers in this field, Dr. Frank Hu, professor of nutrition and epidemiology at the Harvard School of Public Health, said, "The country's big low-fat message backfired. The overemphasis on reducing fat caused the consumption of carbohydrates and sugar in our diets to soar. That shift may be linked to the biggest health problems in America today." Another expert, Dr. Walter Willett, chairman of the department of nutrition at the Harvard School of Public Health, said, "Fat is not the problem."
Last month, Martha Rose Shulman of the New York Times Recipes for Health section, wrote that she's taken the "no low-fat pledge." Shulman writes, "I took a pledge the other day that will surprise my longtime followers. It even surprised me. I pledged to drop the term 'low-fat' from my vocabulary."
Shulman, an influential food and recipe writer with over 25 books to her name, has long promoted low-fat and light cooking, but now writes, "There are many recipes in my cookbooks from the 90s that now look and taste dated to me. I've put back some of the oil and cheese that I took out when editors were telling me to keep total fat at 30 percent of total calories-a concept that is now obsolete even among policymakers."
She and a room full of "nutrition scientists, dietitians, doctors, chefs and food service titans" recently listened to experts on nutrition debunk some of the common fat myths. Dr. Dariush Mozaffarian, who co-directs the program in cardiovascular epidemiology at Brigham and Women's Hospital and Harvard Medical School and is an assistant professor at the Harvard School of Public Health, was also there and said, "No randomized trial looking at weight change has shown that people did better on a low-fat diet. For many people, low-fat diets are even worse than moderate or high-fat diets because they're often high in carbohydrates from rapidly digested foods such as white flour, white rice, potatoes, refined snacks and sugary drinks."
These are clear indications that an important tipping point in the mainstream understanding of fat and nutrition is underway. But it did take some time. Back in 2002, Gary Taubes wrote about it in the New York Times magazine, laying out a fine deconstruction of the low-fat premise presented to the American people. He pointed out that the science behind this recommendation was never proven and was actually based on "a leap of faith" (more on this here).
In 2001, Dr. Hu, writing in the Journal of the American College of Nutrition, noted, "It is now increasingly recognized that the low-fat campaign has been based on little scientific evidence and may have caused unintended health problems." Or, as Michael Pollan pithily puts it in his In Defense of Food, "The amount of saturated fat in the diet may have little if any bearing on the risk of heart disease, and the evidence that increasing polyunsaturated fats in the diet will reduce risk is slim to nil."
This brings up several important issues in the fat debate. It is still widely held that what matters are the types of fat we consume. Even in Shulman's article on her fat re-education, there are contradictions--it's clear she just can't get her head around the idea that saturated fats may indeed be healthy. She writes, "Saturated fat--the kind found in animals and dairy products, as well as in any hydrogenated fat--is also regarded as a less healthy fat because it raises LDL cholesterol, or 'bad' cholesterol in the blood, and this kind of cholesterol is related to heart disease. But even saturated fat is not so bad compared to refined carbohydrates, the doctors say, and if we were to eliminate it from our diet we would also be eliminating many foods that are also rich in healthy fats, like fish, whose omega-3 fatty acids are vital to good health."
But as Pollan points out, the idea that saturated fats are a less healthy fat just isn't true, as the picture is fairly complex. Indeed, most foods are composed of a many different types of fats. For example, half the fat found in beef is unsaturated and most of that fat is the same monounsaturated fat found in olive oil. Lard is 60 percent unsaturated and most of the fat in chicken fat is unsaturated as well, according to Taubes 2008 book Good Calories, Bad Calories. In his New York Times article he writes, "Even saturated fats-AKA, the bad fats--are not nearly as deleterious as you would think. True, they will elevate your bad cholesterol, but they will also elevate your good cholesterol. In other words, it's a virtual wash." Taubes continues, "Foods considered more or less deadly under the low-fat dogma turn out to be comparatively benign if you actually look at their fat content. More than two-thirds of the fat in a porterhouse steak, for instance, will definitively improve your cholesterol profile (at least in comparison with the baked potato next to it); it's true that the remainder will raise your L.D.L., the bad stuff, but it will also boost your H.D.L. The same is true for lard. If you work out the numbers, you come to the surreal conclusion that you can eat lard straight from the can and conceivably reduce your risk of heart disease."
Nearly every day new research and studies come out debunking the popular fat myths; despite this, misinformation persists. On the Mayo Clinic's Web site, saturated fats are lumped in with trans-fats under the banner "harmful dietary fat" and the site claims that saturated fat can increase your risk of cardiovascular disease and Type 2 diabetes.
The link to cardiovascular disease is a tenuous one at best--the idea being that saturated fats raise your cholesterol and triglyceride levels which in turn leads to cardiovascular disease. But according to the most recent studies, including one reported in the Los Angeles Times article, this is not true. "Contrary to what many expect--dietary fat intake is not directly related to blood fat. Rather, the amount of carbohydrates in the diet appears to be a potent contributor," Marni Jameson writes.
And during a symposium called "The Great Fat Debate: Is There Validity In the Age-Old Dietary Guidance?" at the American Dietetic Association's Food and Nutrition Conference and Expo, four leading experts agreed that replacing saturated fat with carbohydrates is likely to raise the risk of cardiovascular disease. Dr. Walter Willett said, "If anything, the literature shows a slight advantage of the high fat diet."
And as for diabetes, there is no data to support the notion that a high-fat diet increases the risk for diabetes. Again, if anything, the opposite appears to be true. In a 2008 study reported in the Los Angeles Times article, obese men and women with metabolic syndrome (a precursor to diabetes) that went on a high saturated-fat, low-carb diet saw their triglycerides drop by 50 percent and their levels of "good" H.D.L. cholesterol increase by 15 percent.
But old dietary habits die hard and convincing people that what they've been told for the past 50 years is just plain wrong, is a hard sell. Not only that, but the continued recommendations to eat low-fat versions of foods (as in the USDA's latest dietary guidelines and on the Mayo Clinic's Web site) don't help. Americans are confused about nutrition and disease and it's only getting more complex with corporations claiming to make healthier foods (see Mark Bittman's take on McDonald's oatmeal and my take on Wal-Mart's health washing).
Keep in mind, there is one type of fat that is implicated in high cholesterol, atherosclerosis, heart disease, and diabetes: Trans-fat. Trans-fats raise bad cholesterol, lower good cholesterol, and increase triglycerides, they also promotes inflammation and insulin resistance, according to a 2000 article in the Journal of the American College of Nutrition. This points to the one basic axiom that always hold true: Eat real, whole foods and nothing else--now, if we could only just all agree on what those are.
This post originally appeared on Civil Eats
Follow Kristin Wartman on Twitter: www.twitter.com/kristinwartman
David Katz, M.D.: Is All Saturated Fat The Same?
Carole Carson: Obesity: Character Flaw or Neurochemical Disease?
Susan B. Dopart, M.S., R.D., C.D.E.: In Defense of Fat: 7 Surprising Facts
"But even saturated fat is not so bad compared to refined carbohydrates, the doctors say, and if we were to eliminate it from our diet we would also be eliminating many foods that are also rich in healthy fats, like fish, whose omega-3 fatty acids are vital to good health." Please note: Omega-3's are polyunsaturated not saturated fats.
"Keep in mind, there is one type of fat that is implicated in high cholesterol, atherosclerosis, heart disease, and diabetes: Trans-fat." The article fails to point out that many saturated fats (i.e meats, whole milk, butter) are accompanied with naturally ocurring trans fats as fats are mixed and correctly ponted out earlier in the article. Eating more saturated fats may also increase these trans, which in term are harmful.
And the phrase you want is "which in turn", not "which in term."
"turn" vs "term", you're right, was typing fast, lol.
I try and stay away from "high" anything diets. A diet "high" in saturated fat is probably not as healthy as a diet with moderate levels of saturated fat. No?
I agree, it's important to eat real, whole foods, wild if possible. I haven't eaten meat or poultry (I eat fish,mostly that I catch) in 12 years but the new science has almost convinced me to try a little grass fed beef and see how it goes down. I used to eat a lot of meat but decided to give it up.
We are basically carnivores. Carbs were scarce to non-existent in pre-farming days (think Eskimos and many Islanders). One author mentions that a paleontologist can immediately tell a modern man's skeleton from a hunter-gatherers', the later being much sturdier, more muscle connections, no cavities, etc. Also, many studies were done of "primitives" by missionary doctors a hundred years ago and they found minimal diabetes, heart disease, gastro-intestinal disorders, etc.
Doug
Interesting to see some cling to the low fat Ancel Keys failings even when the US and rest of developed countries continue to swell with the obesity epidemic brought on by processed carbs.
No Mr. and Mrs. America, your not fat, just well marbled!
Brought to you by General Mills;)
There's a book called "Catching Fire: How Cooking Made Us Human" by Richard Wrangham. His thesis is that cooking allowed us to become human. It allowed our digestive system to get smaller, freeing up metabolic energy to grow a larger brain. Fascinating book.
While fat tastes good, there really aren't very many high-fat foods people can easily and readily eat.
Most of what was called "too fatty" by the low-fat crowd still end up being food items with 20-30% of their calories from fat. Even "fatty" junk like ice-cream, fast-food hamburgers are far more calories from carbs than fat (which is why they make you fat).
I also think that a reduction in animal products is healthful (with many other benefits.)
Both sides have some points. I am tired of the carbs vs fat debate. We eat too many processed foods and we eat too much of all calorie sources (fats, protein = strain on kidneys and carbohydrates.)
Fructose in fruit is exactly the same substance as any other fructose, but real fruit has far less than do those sugary drinks and processed food-like substances in supermarkets and convenience stores. It's hard to eat enough fruit to have the same effect as a sugary Latte in the morning and a Coke in the afternoon. Throw in a nice fruit juice for lunch, even sweetened with natural grape juice, and you've gone way beyond the amount of fructose you'd get from real fruit.
As long as no one tries to oversimplify the story, we're OK.
Sucrose is broken down into glucose and fructose by an enzyme in the intestine.
http://watcut.uwaterloo.ca/webnotes/Metabolism/page-4.1.html
Didn't bother to check out any of his links .... anyone know any more about the "natural vs. hydrogenization" conversation when it comes to fats?
I think you can safely assume that whatever problems a food may have, if it is natural it is better. That is why even fructose in fruit is not nearly the problem that high fructose corn syrup is. Once you start breaking things down or transforming them in some way it is impossible to tell what you will end up with and what the effects on health will be.
I think trans bonds in milk or beef can be metabolized. Trans bonds in polyunsaturated oils trap 18 or even more carbons and I have never seen an explanation of how mammals can break one of these franken-molecules down and we excrete little fat through skin or shedding gut cells. Unfortunately we absorb fats whole so have no protection from them except not to consume. You are right on about fruit. Dr. Lustig on the People's Pharmacy defined the fructose problem well.
MCFAs are different than other forms of fat, because unlike other fats, it is able to break down without the aid of the pancreas making it immediately available to the liver through the portal vein. The liver then converts the MCFA into instant energy. It is not bundled into a triglyceride, it does not store to fat, and it does not raise blood sugar levels (unlike carbohydrates). Furthermore, once the MCFA arrives at the cell, it is able to permeate the cell’s membranes without using any additional enzymes, thus, supplying the mitochondrial organs with instant energy. Peace