Systematic Review Finds No Grounds for Current Warnings Against Saturated Fat

Saturated Fat

Story at-a-glance

  • Despite low-fat diets having become the norm over the past six decades, American levels of heart disease, obesity, and high cholesterol have skyrocketed
  • Four years ago, a meta-analysis came to the conclusion that there’s “no significant evidence... that saturated fat is associated with an increased risk for coronary heart disease”
  • Another recent meta analysis also found that saturated fats, which have the longest history of being (wrongfully) demonized were found to have no effect on heart disease risk
  • The only fat found to really promote heart disease was trans fat (found in margarine, vegetable shortening, and partially hydrogenated vegetable oils)
  • To protect your heart health, you need to address your insulin and leptin resistance, which is the result of eating a diet too high in sugars and grains


This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.

By Dr. Mercola

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For well over half a century, the media and a majority of health care officials have warned that saturated fats are bad for your health and lead to a host of negative consequences, including high cholesterol, obesity, and heart disease.

The American Heart Association began encouraging Americans to limit dietary fat, particularly animal fats, in order to reduce their risk of heart disease as far back as 1961. And as of 2010, the current recommendations from the US Department of Agriculture1 (USDA) call for reducing your saturated fat intake to a mere 10 percent of your total calories or less.

Worse yet, fat was virtually removed entirely from the latest USDA "food pyramid," now called "MyPlate." Except for a small portion of dairy, which is advised to be fat-free or low-fat, fats are missing entirely!

But despite low-fat diets having become the norm over the past six decades, American levels of heart disease, obesity, and high cholesterol have skyrocketed, far surpassing such disease rates in modern-day primitive societies that still use saturated fat as a dietary staple.

Clearly there's a lot of confusion on the subject of saturated fats, even among health care professionals. Fortunately, the tide is starting to turn, as the truth about these correlations is becoming more glaringly obvious.

Systematic Review Finds No Grounds for Current Guidelines on Fat

Four years ago, a meta-analysis published in the American Journal of Clinical Nutrition2 came to the conclusion that there's "no significant evidence... that saturated fat is associated with an increased risk for coronary heart disease."

Now, yet another meta-analysis of 49 observational studies and 27 randomized controlled trials published in a major publication, the Annals of Internal Medicine 3,4,5 has reached the same conclusion. In all, the analysis included data from more than 600,000 people from 18 countries, and according to the authors:

"[C]urrent evidence does not clearly support cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats."

The study looked at four categories of dietary fats: saturated fats; polyunsaturated fats, such as omega-3 and omega-6; monounsaturated fats such as olive oil; and trans fats. Saturated fats, which have the longest history of being (wrongfully) demonized, were found to have no effect on heart disease risk.

Ditto for monounsaturated fats such as olive oil, which are generally recognized as being heart healthy. Both omega-3s and omega-6s were also deemed to be beneficial6, 7 for heart health. The only fat found to really promote heart disease was trans fat (found in margarine, vegetable shortening, and partially hydrogenated vegetable oils). Fortunately, the US Food and Drug Administration (FDA) has already taken steps to remove these harmful fats from the food supply.

They plan to do this by removing partially hydrogenated oils—the primary source of trans fats—from the list of "generally recognized as safe" (GRAS) ingredients. If the proposal goes through, it would be a big step in the right direction. The World Health Organization (WHO) has also previously called for the elimination of trans fats from the global food supply.8

According to the authors of the featured analysis, the lack of correlation between saturated fat and heart disease really should trigger a review of our current dietary guidelines for heart health. Others still vehemently disagree, to the detriment of anyone listening to their recommendations. As reported by

"In response to the study, the American Heart Association says its guidelines remain the same. For heart health, it recommends a diet rich in fruits and vegetables, whole grains, fish, nuts, and unsaturated fats. Less than six percent of the diet should include saturated and trans fats, the association says."

Sugar, Not Fat, Drives Heart Disease

Many health experts now believe that if you are insulin or leptin resistant, as 85 percent of the US population is, you likely need anywhere from 50 to 85 percent of your daily calories in the form of healthful fats for optimal health. Research also increasingly points to refined carbohydrates (particularly processed fructose) as being the real culprit behind rising heart disease rates.

In the 1960s, British physician John Yudkin was among the first to challenge Ancel Keys' hypothesis that saturated fat caused heart disease by raising cholesterol, stating that SUGAR is the culprit in heart disease—not saturated fat.

Unfortunately, Keys was a politically powerful figure, and it was his flawed cholesterol theory that ultimately gained firm traction within the medical establishment. By the 1970s, you were considered a total quack if you supported Yudkin's sugar theory.

In more recent years, Yudkin's work has been proven prophetic—and far more accurate than Keys' ever was. For example, a 2010 study published in the American Journal of Clinical Nutrition10 found that when you replace saturated fat with a higher carbohydrate intake, particularly refined carbohydrate, you exacerbate insulin resistance and obesity, increase triglycerides and small LDL particles, and reduce beneficial HDL cholesterol.

The authors state that dietary efforts to improve your cardiovascular disease risk should primarily emphasize the limitation of refined carbohydrate intake and weight reduction.

Courtesy of the low-fat myth taking firm hold, this is the polar opposite of what actually occurred over the past half century. While saturated fat consumption was dramatically reduced in most people's diet, refined carbohydrate intake dramatically increased. Today, refined fructose is added to virtually every kind of processed food and beverage on the US market.

One of the reasons for all this added sugar is because when you remove fat, you lose flavor. So sugar is used to add flavor back in. Consumption of harmful trans fat (which for decades was touted as a healthier alternative to saturated animal fat) also radically increased, starting in the mid-1950s.

Replacing Saturated Fats with Carbohydrates Has Led to Elevated Disease Risks Across the Board

In the final analysis, it seems clear that one seriously flawed hypothesis gaining foothold in the minds of the medical establishment has led to a decades-long snowball effect of dietary recommendations that have both altered the food supply for the worse, and led to an avalanche of otherwise avoidable chronic diseases.

Evidence of this was recently highlighted in an excellent editorial in the journal Open Heart.11 In it, research scientist and doctor of pharmacy James J. DiNicolantonio reviews the cardiometabolic consequences of replacing saturated fats with carbohydrates, which includes the following:

Shift to overall atherogenic lipid profile (lower HDL, increased triglycerides and increased ApoB/ApoA-1 ratio) Increased risk of coronary heart disease, cardiovascular events, and death from heart disease and increased overall mortality (all causes) Increased thrombogenic markers
Increased oxidized LDL Increased inflammation Reduced HDL
Impaired glucose tolerance, higher body fat, weight gain, obesity, and diabetes Increased small, high-density LDL particles Increased risk for cancer

Heart Disease Prevention 101

Groundbreaking research by the likes of Dr. Robert Lustig and Dr. Richard Johnson (author of the books, The Sugar Fix and The Fat Switch) clearly identifies the root cause of heart disease—and it's not fat. It's refined fructose, consumed in excessive amounts. Their research, and that of others, provides us with a clear solution to our current predicament. In short, if you want to protect your heart health and avoid a number of other chronic disease states, you need to address your insulin and leptin resistance, which is the result of eating a diet too high in sugars and grains.

For those of you still concerned about your cholesterol levels, know that 75 percent of your cholesterol is produced by your liver, which is influenced by your insulin levels. Therefore, if you optimize your insulin level, you will automatically optimize your cholesterol, thereby reducing your risk of both diabetes and heart disease. To safely and effectively reverse insulin and leptin resistance, thereby lowering your heart disease risk, you need to:

  • Avoid sugar, processed fructose, grains if you are insulin and leptin resistant, and processed foods
  • Eat a healthful diet of whole foods, ideally organic, and replace the grain carbs with:
    • Large amounts of vegetables
    • Low-to-moderate amount of high-quality protein (think organically raised, pastured animals)
    • As much high-quality healthful fat as you want (saturated and monounsaturated from animal and tropical oil sources). Most people actually need upwards of 50-85 percent fats in their diet for optimal health—a far cry from the 10 percent or less that is currently recommended. Sources of healthful fats to add to your diet include: avocados; butter made from raw grass-fed organic milk; raw dairy; organic pastured egg yolks; coconuts and coconut oil; unheated organic nut oils; raw nuts and seeds; and grass-fed and finished meats

A third "add-on" suggestion is to start intermittent fasting, which will radically improve your ability to burn fat as your primary fuel. This too will help restore optimal insulin and leptin signaling.

Saturated Fat and Cholesterol Are Both Necessary for Optimal Health

Saturated fats from animal and vegetable sources provide a number of important health benefits, and your body requires them for the proper function of your:

Cell membranes Heart Bones (to assimilate calcium)
Liver Lungs Hormones
Immune system Satiety (reducing hunger) Genetic regulation

Cholesterol also carries out essential functions within your cell membranes, and is critical for proper brain function and production of steroid hormones, including your sex hormones. Vitamin D is also synthesized from a close relative of cholesterol: 7-dehydrocholesterol. Your body is composed of trillions of cells that need to interact with each other. Cholesterol is one of the molecules that allow for these interactions to take place.

For example, cholesterol is the precursor to bile acids, so without sufficient amounts of cholesterol, your digestive system can be adversely affected. It's also critical for synapse formation in your brain, i.e. the connections between your neurons, which allow you to think, learn new things, and form memories. In fact, there's reason to believe that low-fat diets and/or cholesterol-lowering drugs may cause or contribute to Alzheimer's disease.12 Low cholesterol levels have also been linked to violent behavior, due to adverse changes in brain chemistry.

To further reinforce the importance of cholesterol, I want to remind you of the work of Dr. Stephanie Seneff, a research scientist at the Massachusetts Institute of Technology (MIT) who most recently made a giant splash in the world of science with her discovery of how glyphosate acts to destroy human health. According to her theory on cholesterol, it combines with sulfur to form cholesterol sulfate, which helps thin your blood by serving as a reservoir for the electron donations you receive when walking barefoot on the earth (also called grounding). She believes that, via this blood-thinning mechanism, cholesterol sulfate may provide natural protection against heart disease. In fact, she goes so far as to hypothesize that heart disease is likely the result of cholesterol deficiency—which of course is the complete opposite of the conventional view.

For Optimal Heart Health, Balance Your Omega-3 to Omega-6 Ratio

Another critical fat your body needs for optimal health is animal-based omega-3. Omega-3 deficiency can cause or contribute to very serious health problems, both mental and physical, and may be a significant underlying factor of up to 96,000 premature deaths each year. Again demonstrating the abject failure of government guidelines to promote health, the 2011 "food pyramid" (MyPlate) doesn't even mention omega-3. To remedy this gross "oversight," I've created my own Food Pyramid for Optimal Health, which you can print out and share with your friends and family.

Dr. Mercola's Food Pyramid for Optimal Health Preview

As for omega-6 fats, it's important to understand that while you do need them, the most important factor is the ratio between omega-3 and omega-6. The ideal ratio is thought to be anywhere between 1:1 and 1:5, but the typical Western diet is between 1:20 and 1:50 in favor of omega-6, courtesy of an overabundance of industrially processed vegetable oils. As an oversimplification, omega-3s are anti-inflammatory, whereas omega-6s are pro-inflammatory. Hence, when omega-6 is consumed in excess, it can become problematic — and even more so if it's damaged through processing. I firmly believe that increasing your omega-3 and reducing industrialized omega-6 oils is a profoundly important and simple shift in diet that you need to address. For a more complete discussion of the differences between types of dietary fat, omega-3 versus omega-6, DHA, EPA, etc., please refer to our comprehensive fatty acids overview.

Preventing Heart Disease Is Within Your Control

The take home message here is that eating saturated fats like butter, coconut oil, and avocados will not increase your risk of heart disease. On the contrary, it is extremely important for optimal health, including your heart and cardiovascular health. What WILL dramatically raise your risk of heart disease and any number of other chronic health problems is refined carbohydrates, including sugar, fructose, and all unsprouted grains. Replacing saturated fats with trans fats and carbohydrates is precisely what has led to a literal "world of hurt" over the past several decades. Fortunately, reversing this trend is rather simple, but it will require you to buck a very stubborn status quo—albeit a status quo that is starting to crumble at the foundation, as more and more researchers are coming to the conclusion that we've had it all backwards. So, in summary, if you want to prevent heart disease:

  • DO eat unprocessed saturated animal fats. Many may benefit from increasing the healthful fat in their diet to 50-85 percent of daily calories
  • AVOID all sugars, including processed fructose and grains if you are insulin and leptin resistant. It doesn't matter if they are conventional or organic, as a high-sugar diet promotes insulin and leptin resistance, which is a primary driver of heart disease
  • DO exercise regularly, as physical activity along with a healthy diet of whole, preferably organic, foods may be just as potent—if not more potent—than cholesterol-lowering drugs
  • AVOID cholesterol-lowering drugs such as statins, as the side effects of these drugs are numerous while the benefits are debatable. In my view, the only group of people who may benefit from a statin drug are those with genetic familial hypercholesterolemia. This is a condition characterized by abnormally high cholesterol, which tend to be resistant to lifestyle strategies like diet and exercise


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