The 2026 Levels Guide to saturated fat
Depending on your current health and lifestyle, saturated fat may be less harmful than once thought. Discover the latest science on this lipid and what happens when you eat it.
Depending on your current health and lifestyle, saturated fat may be less harmful than once thought. Discover the latest science on this lipid and what happens when you eat it.
For decades, medical experts and federal guidelines have told us that reducing saturated fat is key to good health. We were warned that eating foods higher in saturated fat---like red meat, full-fat dairy, eggs, and coconut oil---would increase our risk of heart attack, stroke, and other cardiovascular problems. But for more than 15 years, research has cast doubt on this advice, suggesting, at most, a weak link between saturated fat and heart disease. Experts say it may not be fair to single out saturated fats when someone's overall dietary pattern has a much larger influence on cardiometabolic disease risk than any one isolated nutrient.
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Despite this, current Dietary Guidelines for Americans and recommendations from the American Heart Association still suggest that everyone age 2 and older limit their saturated fat to less than 10 percent of daily calories. So what's the best approach?
This guide will help you navigate the latest science on saturated fat, explain what happens when you eat it, and determine how much may be appropriate for you.
What is saturated fat?
Saturated fats are found in the highest amounts in animal-derived foods such as meat (particularly red meat such as beef, lamb, and pork; and skin-on poultry) and full-fat dairy, as well as tropical oils like coconut oil and palm oil. Saturated fatty acid molecules consist of a series of carbon atoms linked together by single bonds, creating a relatively straight molecular structure. This allows the molecules to pack tightly together, so most saturated fats remain solid at room temperature (think: coconut oil, butter). Unsaturated fats, on the other hand, are liquid at room temperature due to the presence of one or more double bonds that create bends in their molecular structure.
A food that contains saturated fat has different proportions of several different saturated fatty acids (SFAs). There are 10 major naturally occurring SFAs, differentiated by the number of carbon atoms they contain (their carbon chain length can be short, medium, or long). The main SFAs consumed in most human diets include stearic, palmitic, myristic, and lauric acids, but we also consume lesser amounts of others.
How does saturated fat affect cholesterol and heart health?
The answer is more nuanced than previously understood. Since the 1950s, saturated fat has consistently been blamed as one of the main dietary contributors to cardiovascular disease and cardiac events, including heart attack and stroke. In what has been dubbed the "diet-heart hypothesis" or the "lipid hypothesis," physiologist Ancel Keys and other experts first promoted the idea that saturated fat consumption causes cardiovascular disease by raising blood levels of cholesterol. The proposed mechanism: Elevated low-density lipoprotein (LDL) cholesterol from eating too much saturated fat increases the amount of cholesterol and fat deposited in artery walls, which then leads to a buildup of fatty plaque in arteries (atherosclerosis) and cardiovascular disease.
Today, LDL cholesterol is still widely considered the "bad" form of cholesterol, and we know that when LDL-cholesterol concentrations are high, it has the potential to enter the endothelial lining, or walls, of arteries, especially when they are damaged or inflamed due to factors like high blood pressure, high blood glucose, smoking, and obesity. Once inside, LDL can become oxidized into oxLDL by circulating free radicals, triggering an inflammatory response that recruits immune cells called macrophages to the area. As macrophages engulf and try to remove oxLDL, they transform into foam cells that accumulate in the artery wall as fatty streaks, and eventually as hardened plaques that can restrict blood flow or rupture to form clots that lead to heart attack or stroke. (But, just because LDL cholesterol has the potential to trigger these events doesn't mean it always will---other factors can make it more or less dangerous, which we'll cover later.)
On the flip side, high-density lipoprotein (HDL) cholesterol---widely considered the "good" kind---helps prevent atherosclerosis in several ways: by removing cholesterol from foam cells lining the arteries and transporting it to the liver for excretion or redistribution, by reducing blood vessel inflammation, and by taking up free radicals that might otherwise oxidize LDL cholesterol.
Research also tells us that saturated fat does, in fact, raise LDL cholesterol in some people. The likely mechanism: High intake of saturated fats suppresses the activity of LDL receptors on liver cells (probably through its interactions with a protein in cells called SREBP2), thereby decreasing the transport of LDL cholesterol from the blood into cells. This not only causes LDL cholesterol to build up in the bloodstream, it also causes a relative depletion of cholesterol inside liver cells, which prompts these cells to synthesize more cholesterol. Newly synthesized cholesterol is then packaged in the liver, often into very low density lipoprotein (VLDL) particles, which are released into the bloodstream, where they eventually become LDL cholesterol. Reducing saturated fat intake, on the other hand, has the opposite effect and increases the number of LDL receptors on liver cells, which allows the liver to clear more LDL cholesterol from the blood.
Interestingly, research suggests that the individual SFAs mentioned earlier can have somewhat different effects in the body. For example, strong evidence suggests that palmitic, myristic, and lauric acids can all raise levels of potentially harmful LDL cholesterol. When comparing each, studies suggest that myristic acid raises LDL cholesterol the most, followed by palmitic acid, and then lauric acid. However, there's no consensus on the degree to which each of these raises LDL, and, at least for now, the differences appear to be relatively minor.
These SFAs also simultaneously raise beneficial HDL cholesterol to varying degrees, with some research suggesting that lauric acid increases HDL the most. Lauric acid, which makes up about half of the SFAs in coconut oil, is a medium-chain fatty acid or medium-chain triglyceride (MCT). Some experts claim that MCTs should not be judged the same as other SFAs, given their neutral to potentially beneficial impact on heart health. Given the fact that most whole and minimally processed sources of saturated fat contain a mixture of several different SFAs, however, it's unclear how meaningful these differences would be in a real-world setting.
In comparison to other SFAs, stearic acid is unique in that it has a neutral impact on cholesterol---and when it replaces other SFAs, it can reduce LDL cholesterol. Stearic acid is naturally found in foods like cocoa butter, meat, poultry, eggs, and dairy, but again, these foods also contain significant amounts of other SFAs, so they can still influence cholesterol levels. Interestingly, though, while the overall content of saturated fat is similar between grass-fed and grain-fed beef, some research suggests grass-fed meat tends to have a higher proportion of stearic acid and a lower proportion of cholesterol-elevating myristic and palmitic acids---potentially making it a smarter choice, though more research is needed to determine how grass-fed beef impacts people with high cholesterol compared to grain-fed beef.
As you're reading this article, keep in mind that most studies included only consider total saturated fat content and don't differentiate between intake of individual SFAs. It's also important to consider the following important caveats about the risks and benefits of saturated fats.
Why saturated fat seems to affect some people differently than others
Research shows that increasing saturated fat intake may elevate LDL cholesterol levels in some, but not all, people. That's because there can be significant individual variability when it comes to saturated fat's effects in the body. In one study, increasing saturated fat intake by 6 percent of total energy intake resulted in a varied LDL cholesterol response among participants, ranging from a 45 percent increase in LDL to a 20 percent decrease in LDL.
Potential mechanisms responsible for this varied response include certain variants of the apoE gene, which regulates the clearance of LDL and other lipoproteins from the blood. For example, the apoE4 variant changes the way LDL cholesterol particles bind to other particles in the blood, and this can ultimately decrease the number of LDL receptors on cell surfaces and impair LDL cholesterol clearance, thereby raising levels. Saturated fat consumption appears to exacerbate this: Carriers of the apoE4 variant tend to have the least favorable blood lipid profiles (higher LDL and lower HDL) when consuming diets high in saturated fat, total fat, and cholesterol compared to non-carriers. But when they decrease their intake of these nutrients, they experience the greatest improvements in blood lipids. A 2008 study also shows that apoE4 carriers with the highest saturated fat intake have seven times the risk of developing dementia compared to non-carriers with the lowest intake.
Your gut may also play a role in how well you tolerate saturated fat: A diverse, healthy gut microbiome produces short-chain fatty acids (SCFAs), such as butyrate and propionate, some of which have been shown to curb inflammation and decrease your body's production of cholesterol. While genetic factors affect gut microbiome composition to a point, anyone can boost production of beneficial SCFAs by increasing consumption of fiber-rich plant foods.
Individual response to saturated fat can impact more than just LDL cholesterol, too. For example, research has found that carriers of an APOA2 gene variant (the APOA2 265T>C polymorphism) are more likely to have a higher BMI and obesity when eating a diet high in saturated fats.) (more than 22 grams per day) but not when saturated fat intake is low.
There's a lack of consensus about LDL cholesterol and cardiovascular risk
New research and reanalysis of old research suggest that increased LDL cholesterol doesn't always translate to increased cardiovascular risk, thus calling the diet-heart hypothesis into question. For example, later analysis of Keys' famous Seven Countries Study (SCS)---the first study to strongly link saturated fat intake to deaths from cardiovascular disease, which shaped our modern dietary guidelines---revealed significant flaws in its design, methodology, and interpretation of its results. Case in point: A 1989 reanalysis of SCS data found that coronary heart disease-related death was most strongly associated with intake of "sweets" (defined as sugary products and pastries), not saturated fats, as was initially reported.
More recently, a 2022 research review analyzing data from more than 30 observational studies, randomized controlled trials, systematic reviews, and meta-analyses published between 2010 and 2021 found that, collectively, there is a lack of statistically significant data linking saturated fats to cardiovascular disease risk, events, and mortality. According to the authors, the majority of research does not support drastically limiting dietary intake of saturated fat for the prevention of heart disease.
Included in the review was a 2017 analysis of the ongoing PURE (Prospective Urban Rural Epidemiology) study---one of the largest ever epidemiological studies, observing 135,000 people from 18 countries on five continents. The key takeaways:
- People who consumed a higher percentage of their daily energy (calories) from fat and from each type of fat (saturated, monounsaturated, and polyunsaturated)---and therefore decreased the percentage of calories from carbs and protein---had a lower risk of overall mortality compared to people who consumed the least fat.
- There was a neutral association between higher dietary fat intake and cardiovascular disease, heart attack, and cardiovascular-related death.
- The highest saturated fat intake (12 to 15 percent of total energy) specifically was associated with a reduced risk of stroke compared to the lowest intake (2 to 3.4 percent of total energy), and replacing five percent of energy from carbohydrates with an equal amount of energy from saturated fat was associated with a 20 percent lower risk of stroke. While counterintuitive, this association between higher saturated fat intake and reduced risk of stroke supports several previous studies, and potential mechanisms include an increase in HDL cholesterol and ApoA1 (the main protein component of HDL), a decrease in triglycerides, and a reduced risk of atrial fibrillation (with certain types of saturated fat, including stearic acid).
- High carbohydrate intake (more than 60 percent of total energy intake), on the other hand, was associated with a higher risk of overall mortality. Per the study authors, these cumulative findings don't support the current recommendation to reduce total fat to less than 30 percent or saturated fat intake to less than 10 percent of total energy. Instead, people with a high intake of carbohydrates may want to consider replacing some of those with fats.
How can saturated fat raise LDL cholesterol without increased cardiovascular risk?
If we know that LDL cholesterol at least has the potential to accumulate in arterial walls, leading to plaque buildup and hardening of these vessels, how do we make sense of the idea that saturated fat can raise LDL cholesterol but isn't overwhelmingly associated with increased risk of cardiovascular disease, events, and death? There are a few possible explanations:
Saturated fat may be associated with less harmful forms of LDL in some people
LDL cholesterol particles vary in size and density based on what you eat. This can influence their cardiovascular disease-promoting potential. We know that small, dense LDL (sdLDL) cholesterol particles are more likely to enter the endothelial lining of artery walls and undergo oxidation---both key steps in arterial plaque formation. This makes them more likely to contribute to the progression of atherosclerosis compared to larger, more buoyant LDL particles.
Interestingly, some studies show that diets higher in total fat and saturated fat from different sources (e.g. dairy products, red and white meat, and eggs) promote the formation of the large, less harmful LDL cholesterol particles, while diets lower in fat and high in carbohydrates tend to promote the formation of smaller, more harmful LDL cholesterol particles. People with insulin resistance and Type 2 diabetes---which can be caused by regularly consuming a diet high in processed, refined carbs and sugars---also tend to have more small, dense LDL particles, along with higher triglycerides and lower HDL cholesterol compared to people who are more insulin sensitive. Chronic inflammation has also been associated with having more small, dense LDL. (Tip: Levels' advisor Dr. Mark Hyman recommends NMR lipid testing---e.g. NMR LipoProfile or NMR lipoprotein fractionation---as these can measure the total LDL particles and relative amounts of small and large LDL, along with the amount and size of other lipoproteins.)
An important caveat: Some research (but not all) has shown that higher saturated fat intake can increase levels of apolipoprotein B (ApoB)---a protein attached to each of the potentially atherogenic or plaque-forming particles in the blood (LDL, VLDL, IDL, and Lp(a)), making it a better marker of heart disease risk than LDL cholesterol alone. Because saturated fat can increase LDL cholesterol, and because each LDL particle contains one ApoB molecule, it makes sense that ApoB might also increase. (Levels are considered dangerous and more likely to promote atherosclerosis when they exceed 120 or 130 mg/dL.)
People with LDL phenotype B---a genetically influenced blood lipid profile characterized by having a higher proportion of small, dense LDL particles---may be particularly sensitive. In one randomized trial on LDL phenotype B individuals with atherogenic dyslipidemia (high triglycerides, low HDL, and high small, dense LDL), consuming 18 percent of total energy from saturated fat compared to 9 percent of total energy was associated with a 9.5 percent increase in ApoB and a 6.1 percent increase in the concentration of small LDL particles---which may translate to increased cardiovascular disease risk, per the study authors. Similarly, healthy aging expert Dr. Rhonda Patrick, PhD, has stated that for people with high triglycerides and small, dense LDL particles, reducing saturated fat can help lower ApoB. However, for people who don't have these problematic health markers, reducing saturated fat may have no impact on ApoB.
So, if your basic blood lipid panel has already revealed high LDL cholesterol and triglycerides, it may be in your best interest to limit saturated fat intake to the recommended 10 percent or less of your daily calories. And for a more nuanced look at your risk that may help better guide your dietary choices, consider an NMR lipid test or an ApoB test.
Saturated fat may positively impact other CVD risk markers
As several experts have stated, LDL cholesterol is only one factor of many that influences cardiovascular disease risk. And while higher saturated fat intake may increase LDL cholesterol, it may also positively affect other blood lipids in a way that buffers the negative impact of LDL on heart health. For example, a separate 2017 analysis of the PURE study data found that higher intake of total fat and all types of fat (saturated, monounsaturated, polyunsaturated) was also associated with higher HDL cholesterol and ApoA1 (the main protein component of HDL) and lower triglycerides, triglyceride-to-HDL ratio, total cholesterol-to-HDL ratio, and ApoB-to-ApoA1 ratio all of which are considered beneficial for cardiovascular health. (Note: While some research links saturated fat to higher overall ApoB levels, some experts say the ApoB-to-ApoA1 ratio is a better predictor of saturated fat's effect on heart health---and for this ratio, the lower the better.)
A high-quality diet may buffer the negative effects of saturated fat
No one eats saturated fat as an isolated nutrient, you eat it in the form of food---and the body may interact with saturated fats differently depending on the specific foods you eat and your overall diet. This reflects a concept known as the food matrix effect, which basically means that the different components within a food or meal (e.g., macronutrients, fiber, vitamins, minerals, antioxidants, etc.) interact synergistically, leading to effects that are greater than the sum of their parts. In other words, not all saturated fat-containing foods or diets impart the same risk.
To understand this concept better, consider a plain full-fat yogurt and a hot dog. Both of these foods contain saturated fat, but their other nutrients vary considerably---and so does their overall health impact. The yogurt contains potassium, calcium, B vitamins, zinc, selenium, protein, and probiotics, all of which support various aspects of metabolic health. The hot dog contains preservatives, high amounts of sodium, and added sugars. The result: Despite having a controversial nutrient in common, full-fat dairy is not associated with heart disease and stroke risk (fermented full-fat cheese and yogurt are actually associated with reduced stroke risk), while processed meats and animal products have been strongly linked to an increased risk of heart disease and cancer. Other saturated fat-rich foods that are not convincingly linked to cardiovascular disease include unprocessed meats and dark chocolate---likely due to their overall health-promoting food matrix.
Given this food matrix effect, some experts argue that "rather than focus on a single nutrient, the overall diet quality and elimination of processed foods, including simple carbohydrates, would likely do more to improve [cardiovascular disease] and overall health." What this might look like: Eating that full-fat yogurt and grass-fed steak while also loading up on things like fatty oily fish (which are rich in omega-3 fatty acids), berries, leafy greens, nuts, seeds, legumes, avocados, and extra-virgin olive oil to ensure you're getting fiber, antioxidants, unsaturated fats, and other nutrients that fuel your cells, support your gut, and curb inflammation and oxidative stress. So while you're still eating some saturated fats, you're eating them in the context of a robustly healthy diet. Among other benefits, studies suggest this type of approach---which is somewhat similar to a Mediterranean-style diet---may help neutralize excess free radicals and curb the transformation of regular LDL cholesterol into oxidized LDL (oxLDL), the form significantly more likely to promote arterial plaque buildup.
Finally, if you do choose to reduce your saturated fat intake, you'll probably replace those calories with something else---and not all swaps are beneficial. Overall, research suggests that replacing a portion of saturated fats with sources of unsaturated fats (like olive oil, avocado oil, avocados, nuts, seeds, and fatty fish, and especially polyunsaturated fats like vegetable oils) or carbohydrates from whole grains may reduce risk of heart disease. On the other hand, replacing saturated fats with lower-quality carbohydrates (like refined grains and sugars) may increase risk of heart attack. Given this, some experts believe refined carbohydrates and sugars are the bigger dietary culprit in heart disease risk.
Can saturated fats compromise other aspects of metabolic health?
You may have heard theories about other harmful effects of saturated fats, such as their tendency to promote insulin resistance or negatively impact the composition of bacteria in your gut microbiome. But research in these areas is still evolving and not yet conclusive---and other aspects of a person's diet might play a more direct role in both of these processes.
Regarding saturated fat and insulin resistance, research is mixed. This 2014 research review found an association between saturated fat intake and insulin resistance---and in one of the included studies, participants eating a diet high in saturated fats for three months had a 12.5 percent decrease in insulin sensitivity, while participants eating a diet of equal calories but high in monounsaturated fats had an 8.8 percent increase in insulin sensitivity. However, a more recent 2023 systematic review and meta-analysis of 30 randomized controlled trials (RCTs) lasting one to 30 weeks found that replacing at least five percent of total energy from saturated fats with either monounsaturated fats or polyunsaturated fats did not improve insulin sensitivity.
More research is needed on saturated fat's effects on insulin sensitivity, but for now, there's not enough evidence to justify slashing saturated fat intake in the name of improving insulin sensitivity---especially when there are other strategies that appear to be more effective (e.g. reducing sugar and refined carbohydrate intake, eating anti-inflammatory and antioxidant foods, exercising, prioritizing sleep, and managing stress).
Research has also implicated higher saturated fat intake with negative changes in the gut microbiome, including reduced gut microbial richness and diversity, and an increased ratio of Firmicutes to Bacteroidetes (two important bacterial phyla), which is considered a more obesity-promoting and proinflammatory microbiome profile. However, researchers of one systematic review acknowledged that it's hard to pin these negative gut alterations to higher dietary fat intake (or saturated fat, specifically), since eating more fat might coincide with other dietary changes that negatively impact the gut, such as decreased fiber intake. Unless the diets of all people studied are generally the same, it's hard to say for sure whether it's the presence of saturated fat or potentially the absence of something beneficial that harms the gut.
Interestingly, people who have greater gut microbial diversity at baseline are less likely to experience negative changes with increased fat intake. So consider implementing a few habits known to support gut microbiome diversity (e.g., increasing the variety of fiber- and polyphenol-rich plant foods in your diet, eating fermented foods, and getting physical activity).
How much saturated fat is safe per day?
There's no definitive answer, unfortunately. Recent research has helped present a more balanced perspective on saturated fat and its impact, and many experts believe it can be safely included in your diet when consumed via nutrient-dense foods. But the 2020-2025 Dietary Guidelines still recommend keeping saturated fat under 10 percent of total daily calories (22 grams per day on a 2,000 calorie-per-day diet), while the American Heart Association suggests a stricter limit of 6 percent of daily calories (13 grams) and trading them for unsaturated fats.
These guidelines have been widely criticized, as they recommend strict limits on saturated fat without advising people to consider the food source it's coming from. Throughout the years, nutrition researchers and even former members of the Dietary Guidelines Advisory Committee (DGAC) have urged the U.S. Departments of Health and Human Services (HHS) and Agriculture (USDA) to consider lifting limits on saturated fat, but they haven't been successful.
In a 2020 article, former DGAC member and fatty acid researcher Tom Brenna, PhD, expressed concern that saturated fat was being considered in isolation when it should be considered within the context of a larger food matrix. He stated: "Studies show that there are a number of foods that are quite healthy and high in saturated fats. To consider foods just on their saturated fat content is a mistake. In a way, it throws the baby out with the bath water."
That said, the message isn't necessarily "eat as much saturated fat as you want." As previously described, genetic variation, the health of your gut, whether you have sub-optimal blood lipid levels, how much exercise you get, and the other foods you consume may all influence how harmful or benign saturated fat behaves in your body and how much you can eat.
What additional research is needed?
While we've learned a lot about saturated fat in recent decades, a number of shortcomings with the body of existing research make it difficult to draw more definitive conclusions about its health impact. These include:
- A heavy reliance on observational studies that can be confounded by factors like physical activity, overall diet quality, smoking, and genetics
- An emphasis on research measuring saturated fat's association with intermediate risk markers such as LDL cholesterol, which don't necessarily correlate with health risk
- A relative lack of high-quality research studying saturated fat's impact on actual long-term health outcomes (such as CVD and heart attack)
- Frequent reliance on inconsistent and inaccurate measures of saturated fat intake such as food diaries and food frequency questionnaires
- A focus on the quantity of saturated consumed but a lack of focus on the type (e.g., stearic acid versus palmitic acid) and source (e.g., yogurt versus ice cream) of saturated fat
- A tendency to look at saturated fat in isolation and not consider the overall dietary pattern in which it's eaten
- A lack of attention to individual variability, such as genetic variants that might make someone more sensitive to the negative effects of saturated fat
- Inconsistent definitions for what constitutes high or low saturated fat intake
Because of this, experts have called for higher-quality research that accounts for these and other factors. In one 2022 review, the authors emphasized the need for future studies that assess the effects of saturated fatty acids from different food sources on cardiovascular disease risk, as these different foods have distinct fatty acid profiles and other nutrients that may influence cardiometabolic health. They also called for research that compares the impact of saturated fats with other types of fats and carbohydrates on cardiovascular disease risk and mortality in healthy people and those at higher risk. And, they said, this research should include well-designed, adequately powered randomized controlled trials with long follow-up periods.
Conclusion
Our advice: Take a balanced approach. Unless your health care provider specifically advises you to curb saturated fat intake, focus less on limiting saturated fat from all sources and more on eating an overall metabolically healthy diet with a variety of nutrient-dense, minimally processed foods---which might include saturated fat-containing foods like unprocessed meat and dairy.
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