Is Saturated Fat “Bad” for Your Health?

For decades, scientists and health authorities demonized saturated fat.

According to them, eating saturated fat marred your cardiovascular health, which is why they encouraged everyone to greatly limit their intake.

In recent times, the consensus has shifted. 

This is mainly because many popular diet “gurus” claim saturated fat is uniquely healthful and that we need to eat a lot more than doctors recommend to optimize our health.

If you’re perplexed by the disconnect between past and present opinions, this article is for you.

In it, you’ll get an evidence-based answer to the question, “Is saturated fat bad?”

What Is Saturated Fat?

The three primary types of dietary fat are saturated fat, unsaturated fat, and trans fat, all of which are made of carbon, hydrogen, and oxygen. 

What makes saturated fat different is that it’s “saturated” with hydrogen—it contains as much hydrogen as it can without altering its molecular state.

Saturated fat’s “structure” is also slightly different from other types of fat, containing only single bonds between carbon molecules. In contrast, unsaturated fat has at least one double bond between carbon molecules.

Saturated fat is solid at room temperature, and it’s especially concentrated in dairy, red meat, and “tropical oils” (coconut and palm oil, for example).

Why Do People Think Saturated Fat Is “Bad” for You?

In the 1950s, researchers began noticing a link between cardiovascular disease (CVD) risk and saturated fat intake. This led a scientist at the University of Minnesota named Ancel Keys to propose the “diet-heart hypothesis,” the theory that eating dietary fat causes CVD.

Several years later, Keys published the Seven Countries Study (SCS), a long-term study that he believed proved that saturated fat intake and CVD risk are causally linked.

Soon after, leading health authorities, including the American Heart Association and the US Senate Select Committee on Nutrition and Human Needs, accepted his theory and began recommending that Americans limit saturated fat intake to 10% of daily calories (a recommendation that persists today and that more than 70% of Americans exceed).

Is Saturated Fat “Bad” for You?

Many scientists believe saturated fat has been wrongly vilified.

In their opinion, the wholesale adoption of the diet-heart hypothesis was rash on three counts.

First, the Seven Countries Study (SCS) was the basis for the theory. However, the SCS was an observational study, which can only show that two things correlate, not that one causes another.

Second, researchers later identified numerous flaws in the SCS’s methodology.

For example, it didn’t randomly select countries for the study, included only men, collected dietary data from less than 5% of the participants (~500 individuals, or fewer than 100 participants per country), and used non-standardized and non-validated data collection methods, outdated and error-prone statistical methods, and inconsistent follow-up methods.

And third, most studies published since have failed to confirm the SCS’s conclusions.

For instance, in 2021, scientists at the University of Freiburg analyzed 59 systematic reviews of randomized controlled trials (the “gold standard” of scientific research) and cohort studies investigating the effects of dietary fat intake on health. They found that a higher saturated fat intake was not associated with an increased risk of all-cause mortality, CVD, type 2 diabetes, or several cancers.

And this is why most scientists now believe that saturated fat isn’t as bad for our health as we once thought.

This has encouraged some people (carnivore dieters, for example) to go one step further and claim that saturated fat is a “superfood,” capable of conferring a wealth of health benefits. According to them, saturated fat is particularly healthful from unprocessed sources, such as meat and dairy.

Does science agree?

Let’s review a few of the strongest recent studies to find out.

Study #1: Biomarkers of dairy fat intake, incident cardiovascular disease, and all-cause mortality: A cohort study, systematic review, and meta-analysis.

In a 2021 study conducted by scientists at the University of New South Wales, researchers reviewed the data from 18 observational studies investigating the link between saturated fat intake from dairy products and risk of CVD and death.

These studies specifically looked at levels of pentadecanoic and heptadecanoic acid in people’s blood and fat tissue, which are saturated fats in dairy. The higher someone’s levels of these two fatty acids, the more saturated fat they eat from dairy. 

The results showed that the higher a person’s blood levels of pentadecanoic acid, the lower their CVD risk, and that compared to people with the lowest dairy intakes, those with the highest intake had a ~25% lower risk of developing CVD, relatively speaking.

These findings were consistent with the research team’s subsequent systematic review and meta-analysis, which found that when you separate people into thirds based on their pentadecanoic and heptadecanoic acid intake, people in the top third have a 12-to-14% lower risk of CVD than people in the bottom third.

However, this study’s major limitation was that it was observational. This means it can’t show that eating high-saturated fat dairy lowers CVD risk, only that the two correlate. It also meant that the researchers couldn’t distinguish between the different types of dairy products the people ate, so they couldn’t say which were beneficial or if any were deleterious to health.

Study #2: Association of carbohydrate and saturated fat intake with cardiovascular disease and mortality in Australian women.

This 2022 study published in the journal Heart followed nearly 10,000 women for 15 years and looked at the effects of carbohydrate and saturated fat intake on the risk of heart disease, stroke, type 2 diabetes, obesity, high blood pressure, and death.

It found that increased saturated fat intake was not associated with an increased risk of heart disease or death. However, it was linked to lower rates of obesity, type 2 diabetes, and high blood pressure.

It also found that eating a moderate-to-high carb diet (~41-to-44% of daily calories from carbs) was associated with the lowest risk of heart disease but had no effect on the risk of death.

Study #3: Associations between saturated fatty acids from different dietary sources and cardiovascular disease risk in 114,285 UK Biobank study participants.

In a 2021 study conducted by scientists at the University of Oxford, researchers analyzed data on 114,285 UK Biobank (a large-scale biomedical database of British folks) participants to puzzle out the associations between saturated fat from different dietary sources and risks of CVD, ischaemic heart disease (IHD), and stroke.

They found no association between total saturated fat intake and CVD risk. However, eating saturated fat from meat was associated with increased CVD and IHD risk.

For every 5% increase in energy intake from meat, CVD risk increased by 19% and IHD risk increased by 21% (both relative increases). When the researchers adjusted the data based on people’s body mass index (BMI), these associations were weaker—CVD risk increased by 11% and IHD risk increased by 12%, neither of which was statistically significant. 

Saturated fat from dairy decreased IHD risk by 11%, though when the researchers adjusted the data for BMI, this dropped to 9% and wasn’t statistically significant.

The results also showed that replacing 5% of calories from saturated fat in meat with whole grains or fruit and vegetables was associated with a ~14% reduction in stroke risk.

To summarize, this study suggests that saturated fat, particularly from meat, appears to increase CVD and IHD risk, especially if you’re overweight.

Study #4: Dietary Fatty Acids, Macronutrient Substitutions, Food Sources and Incidence of Coronary Heart Disease: Findings From the EPIC-CVD Case-Cohort Study Across Nine European Countries.

Another 2021 study published in the Journal of the American Heart Association investigated the link between different types of fat from various food sources and the risk of developing heart disease.

It was an observational study involving 16,073 people from 9 European countries.

The results showed that saturated fat intake wasn’t associated with a higher risk of heart disease, but various foods containing saturated fat had different effects on heart disease risk.

Specifically, each 1% increase in total energy intake from fish, yogurt, and cheese was associated with a 13%, 7%, and 2% lower risk of heart disease, respectively.

In contrast, for every 1% increase in calorie intake from red meat and butter, heart disease risk increased by 7% and 2%, respectively. 

This suggests that it’s not necessarily saturated fat that’s the issue but the overall composition of your diet that affects CVD risk.

Study #5: Saturated Fatty Acid Chain Length and Risk of Cardiovascular Disease: A Systematic Review.

This 2022 study published in Nutrients evaluated how fatty acid chain length (the number of carbon atoms chained together in fatty acids) affects the development of CVD.

The researchers reviewed 5 “cohort studies” (long-term observational studies) involving almost 311,000 people and found that while long-chain saturated fatty acids tend to increase CVD risk, and short- and medium-chain fatty acids tend to lower or have no effect on CVD risk, the data is too inconsistent to draw firm conclusions.

Importantly, this study showed that different types of saturated fat affect the body differently, suggesting it’s remiss to categorize saturated fat as simply “good” or “bad.”

Based on their findings, the researchers urged people to think less about how saturated fat (as an isolated dietary component) affects health and instead consider how diet and lifestyle as a whole affect CVD risk. 

Your Diet Quality Matters, Too

Many people want to reduce the argument about whether saturated fat is healthy or harmful to “saturated fat is good” or “saturated fat is bad,” but doing so oversimplifies a complex topic.

If you parse the research, you see that most studies’ findings are inconsistent—some say saturated fat is a boon, and others say it’s a bane. And that’s likely because the results reflect not just how saturated fat affects health but how the people in the studies are eating as a whole.

Just because a study finds that eating saturated fat benefits health doesn’t mean eating lots is always optimal, either. 

For example, if you took someone with a standard Western diet and replaced all of the saturated fat from processed foods with saturated fat from unprocessed foods, you’d probably find that their health would improve.

If you then replaced the saturated fat from unprocessed food with monounsaturated fat (MUFA) and polyunsaturated fat (PUFA) from fish, nuts, avocados, and so forth, their health would probably improve more.

In other words, if a person’s diet is poor, substituting unhealthy sources of saturated fat for healthier sources is a good idea. But if they already eat a healthy diet, adding more saturated fat isn’t better.

An elegant example of this comes from a meta-analysis conducted by scientists at Brigham and Women’s Hospital and Harvard Medical School. In this study, the researchers analyzed the effect of replacing saturated fat with PUFA in diets with a high total fat content (35-to-45% daily calories) and high saturated fat content (20% of total fat intake). 

They found that people’s CVD risk fell by 10% every time they replaced 5% of their calories from saturated fat with calories from PUFA.

In other words, if you usually eat 2,000 calories daily, with 400 calories coming from saturated fat, and replace 20 of the calories from saturated fat with PUFA, you’d reduce your risk of CVD by 10% (relatively speaking). 

To further complicate matters, our genes appear to influence how susceptible we are to CVD, which could mean that eating a lot of saturated fat is safe for some but not those susceptible to CVD.

Conclusion

Overall, eating saturated fat probably isn’t as dangerous as many people would have you believe.

That said, I don’t think it makes sense to “overdo” saturated fat (getting ~10% of daily calories from saturated fat is a reasonable rule of thumb), and I recommend getting most of your saturated fat from minimally processed sources, such as meat, dairy, fish, nuts, avocado, and so forth.

Even if you like to eat a high-fat diet, it’s still sensible to limit your saturated fat intake to around 10% of daily calories and instead emphasize MUFA and PUFA, which contribute more to good health.

Luckily, this is easy to do—you basically have to go out of your way to eat foods very high in saturated fat (gobs of coconut butter, for instance) to break this threshold. Even if you eat a lot of red meat and dairy, it’s hard to get more than 10% of your calories from saturated fat.

And if you’d like specific advice about how much of each macronutrient (including fat), how many calories, and which foods you should eat to reach your health and fitness goals, take the Legion Diet Quiz, and in less than a minute, you’ll know exactly what diet is right for you. Click here to check it out.