Is Lard Healthier Than Olive Oil? What Science Says

Olive oil is the healthier choice by a wide margin, and the science on this point is not particularly close. Decades of clinical trials, metabolic studies, and large observational cohorts consistently show that replacing saturated animal fats like lard with monounsaturated fats like olive oil improves cholesterol levels, reduces cardiovascular events, and benefits several other markers of health. That said, the comparison is more interesting than a simple blowout, because lard has a few genuinely surprising properties that challenge the idea that it is nutritionally worthless.

What Actually Differs Between the Two Fats

Lard and olive oil are fundamentally different in their fatty acid makeup. Lard is rich in saturated fatty acids, while olive oil is dominated by oleic acid, a monounsaturated fat that typically accounts for around 70 to 80 percent of its total fat content. Lard does contain some monounsaturated fat of its own, roughly 40 to 45 percent oleic acid depending on what the pig ate, which puts it ahead of butter in this regard. But the remaining saturated fat in lard, mainly palmitic and stearic acid, drives most of the health differences between the two.

The distinction matters because these fatty acid types behave very differently once they enter your body. Saturated fats tend to raise LDL cholesterol by slowing the liver’s ability to clear LDL particles from the bloodstream, while monounsaturated fats either have a neutral effect or actively improve cholesterol handling. And olive oil brings something lard cannot match at all: a suite of bioactive plant compounds, particularly polyphenols, that have their own independent health effects beyond whatever the fat molecules themselves do.

How Each Fat Affects Cholesterol and Blood Vessels

The cholesterol picture heavily favors olive oil. Animal studies across multiple species have consistently shown that saturated fats like lard and butter are “hypercholesterolemic,” meaning they raise LDL cholesterol, relative to monounsaturated and polyunsaturated oils. The mechanism involves both increased LDL production and decreased clearance by the liver.¹ In humans, a randomized trial in people with insulin resistance and abnormal lipids found that swapping lard-derived saturated fat for olive oil’s monounsaturated fat reduced LDL cholesterol by about 7 percent. The improvement came partly from the body breaking down LDL particles faster when olive oil replaced lard in the diet.²

Olive oil’s main fatty acid also appears to protect blood vessels through routes that have nothing to do with cholesterol numbers. Oleic acid has been shown to reduce blood pressure by altering how cell membranes are structured, which changes intracellular signaling in ways that relax blood vessels.³ And in laboratory studies of human endothelial cells, oleic acid reduced the expression of adhesion molecules that recruit immune cells to artery walls, a key early step in the development of atherosclerotic plaques. In one experiment, the expression of VCAM-1, a protein that helps white blood cells stick to vessel walls, dropped by more than 40 percent after cells were incubated with oleic acid.⁴ These are cell and animal studies, not direct proof of what happens in a human eating a salad, but they point toward mechanisms that help explain the clinical trial results.

What Large Human Trials Actually Show

The strongest evidence for olive oil’s cardiovascular advantage comes from the PREDIMED trial, one of the largest and most cited nutrition studies of the past two decades. The trial assigned more than 7,000 people at high cardiovascular risk to either a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with nuts, or a lower-fat control diet. The group eating extra-virgin olive oil had about a 31 percent lower rate of major cardiovascular events like heart attack, stroke, and cardiovascular death compared to the control group.⁵

A more recent analysis of the same trial data looked at the dose-response relationship and found that participants who consumed the most extra-virgin olive oil, averaging about 50 grams per day (roughly three and a half tablespoons), had a 25 percent lower risk of a composite cardiovascular outcome. Those in the very highest consumption bracket, about 60 grams per day, had roughly half the risk compared to the lowest consumers.⁶

No comparable trial exists showing cardiovascular benefits from eating lard. In fact, the evidence runs the other direction. A large analysis of long-term cohort data found that replacing just 5 percent of daily calories from animal fat with plant fat was associated with a 4 to 24 percent lower risk of dying from any cause and a 5 to 30 percent lower risk of dying from cardiovascular disease.⁷ The American Heart Association’s 2017 Presidential Advisory summarized the evidence more bluntly: replacing saturated fat with polyunsaturated vegetable oil in randomized trials cut cardiovascular disease by roughly 30 percent, on par with the benefit seen from statin drugs.⁸

The Polyphenol Advantage

One reason the olive oil versus lard comparison is so lopsided is that olive oil, especially extra-virgin olive oil, contains compounds that lard simply does not. The most studied of these is oleocanthal, a phenolic compound responsible for the peppery, throat-catching sensation you feel with a good extra-virgin oil. Oleocanthal concentrations vary by cultivar and region, but measured levels in Greek olive oils have ranged from roughly 280 to 710 milligrams per kilogram of oil.⁹ Oleocanthal has been shown to share a mechanism of action with ibuprofen, inhibiting the same inflammatory enzymes, though you would need to consume quite a lot of olive oil to approach a therapeutic dose of ibuprofen.

Other polyphenols in extra-virgin olive oil have been shown to promote the process by which cholesterol is removed from artery walls and transported back to the liver for disposal, sometimes called “reverse cholesterol transport.” These compounds also help protect LDL particles from oxidation, which is relevant because oxidized LDL is more likely to contribute to plaque formation than unmodified LDL.¹⁰ Lard has no equivalent bioactive compounds. This means that even if you could somehow equalize the fatty acid profiles of the two fats, olive oil would still bring something extra to the table.

Where Lard Is Not as Bad as You Think

The evidence against lard is strong, but it is worth noting a few findings that complicate the simple “lard is terrible” narrative. In one human crossover study, a lard-based meal actually produced lower levels of circulating triglycerides in the hours after eating compared to equivalent meals made with olive oil or palm olein. The researchers found that serum triglyceride concentrations were significantly lower after the lard meal, and that the inflammatory and hormonal markers they measured, including insulin, glucose, and several inflammatory molecules, did not differ between the fat types in that short postprandial window.¹¹

This does not mean lard is better for your blood fats overall. Postprandial triglyceride levels after a single meal reflect how quickly the body processes the fat from that meal, and saturated fats are handled differently than unsaturated ones in the first few hours. The long-term picture, where LDL accumulates and arterial damage develops over years, still clearly favors olive oil. But the finding is a useful reminder that single-meal snapshots can tell a misleading story if taken out of context.

Lard also contains vitamin D, which olive oil does not. The amount depends heavily on how the pig was raised. Pigs that were exposed to sunlight had roughly three times more total vitamin D in their loin tissue compared to conventionally raised pigs kept indoors, averaging about 1 microgram per 100 grams of tissue for sun-exposed animals versus about 0.35 micrograms for indoor-raised ones.¹² These are modest amounts compared to a supplement or fatty fish, but they are not zero, and for populations with limited vitamin D sources, pasture-raised pork fat contributes something that plant oils cannot.

Effects on the Gut Microbiome

The type of fat you eat reshapes the community of bacteria living in your gut, and this is another area where olive oil and lard diverge. In a mouse study, animals fed a high-fat diet based on extra-virgin olive oil showed greater bacterial diversity in their intestines and a lower proportion of Firmicutes, a bacterial group whose overgrowth has been linked to obesity and metabolic problems. The olive oil diet also boosted the activity of immune-regulating genes and antimicrobial peptides in the gut lining, suggesting that the oil supported the intestinal barrier.¹³

Lard pushed the microbiome in the opposite direction. In a study comparing multiple fat sources in rodents, the lard-fed group showed among the greatest increases in Firmicutes and the steepest drops in Bacteroidetes, a pattern associated with inflammation and metabolic dysfunction. Gut bacterial diversity in the lard group was significantly reduced compared to the control diet.¹⁴ Interestingly, a separate rat study found that when a prebiotic fiber was added to a lard-based diet, it restored some beneficial gut bacteria like Lactobacillus and boosted the activity of protective enzymes in the colon. A similar prebiotic effect was also seen with olive oil diets.¹⁵ This suggests that a high-lard diet is not irreversibly damaging to the gut, but that it starts from a worse baseline than olive oil.

Insulin Sensitivity and Blood Sugar

When it comes to how your body handles blood sugar, the relationship is not quite as straightforward as the cholesterol story. The KANWU study, one of the more carefully designed dietary trials on this topic, found that a diet high in saturated fat impaired insulin sensitivity by about 10 percent, while a diet high in monounsaturated fat (mainly from olive oil) did not change insulin sensitivity at all.¹⁶ Over time, worsened insulin sensitivity is a stepping stone toward type 2 diabetes, so this finding reinforces the pattern: saturated fat from sources like lard moves metabolic markers in the wrong direction, while olive oil does not.

There is, however, one counterintuitive finding worth mentioning. A study in healthy lean men found that a single dose of olive oil acutely reduced both liver-level and whole-body insulin sensitivity by roughly 25 to 28 percent in the hours afterward, while also ramping up glucose production by the liver.¹⁷ This may sound alarming, but it reflects an acute metabolic response to a large bolus of fat, not the chronic metabolic environment that develops over weeks and months of habitual intake. The KANWU study’s multi-week dietary intervention is a much better guide to what actually happens to insulin sensitivity in the real world than what occurs in the hours after a single fat-loading test. Still, the finding is a useful reminder that even healthy fats are not metabolically inert, and that context matters enormously in nutrition research.

Cooking Performance and Heat Stability

One argument frequently made in lard’s favor is that it is more stable at high cooking temperatures because of its higher saturated fat content. Saturated fats do resist oxidation better than polyunsaturated ones, which is why highly polyunsaturated oils like flaxseed or walnut oil are poor choices for frying. But olive oil is not a highly polyunsaturated oil. Its dominant fat is monounsaturated oleic acid, which is reasonably heat-stable, and its polyphenols act as natural antioxidants that further protect the oil during cooking.

Research on heated cooking oils has found that oil fumes produced from heating fats like lard, rapeseed oil, soybean oil, and peanut oil to high temperatures can exhibit mutagenic and genetic toxicity.¹⁸ Lard’s supposed advantage for deep frying is real at extreme temperatures, where its lower polyunsaturated content means fewer volatile aldehyde byproducts, but for the sautéing and moderate-heat cooking most home cooks actually do, extra-virgin olive oil performs well and does not break down into harmful compounds the way some people fear. The popular claim that olive oil “can’t take the heat” is overstated for normal kitchen use.

How Dietary Guidelines Shaped the Debate

Part of the reason this question persists is that dietary fat advice has changed over the decades, and each shift has fueled skepticism about the whole enterprise. The U.S. government first recommended limiting saturated fat in 1977, when the Senate’s Select Committee on Nutrition suggested capping it at 10 percent of total calories.¹⁹ That recommendation has survived in various forms for nearly five decades, though it has been criticized from multiple directions: by low-carb advocates who argue that saturated fat was wrongly demonized, and by some researchers who point out that the original evidence base was weaker than it appeared.

The backlash has led to a popular narrative that “they were wrong about fat all along,” which sometimes gets stretched into the claim that lard, butter, and other animal fats are fine or even superior to vegetable oils. The evidence does not support that leap. What the revisionist history correctly identifies is that the original low-fat advice was too blunt, lumping all fats together as bad and inadvertently encouraging people to replace fat calories with refined carbohydrates, which turned out to be worse. What it does not show is that saturated fat is harmless. The best current evidence, from trials like PREDIMED and from the AHA’s comprehensive review, consistently finds that replacing saturated fat with unsaturated fat, especially from olive oil and similar sources, reduces cardiovascular risk. The error was in the framing, not in the core chemistry.

Appetite and Brain Signaling

An emerging area of research explores how different fats affect hunger signals in the brain. A rat study examining hypothalamic gene expression after exposure to different fats found that extra-virgin olive oil lowered the expression of a receptor involved in satiety signaling, while palm oil increased the expression of neuropeptide Y, a potent appetite stimulator, and decreased CART, which helps suppress appetite.²⁰ The research is very early-stage and done in animals, so drawing firm conclusions about whether olive oil or lard makes you hungrier or fuller would be premature. But it opens an interesting question: if different fats talk to the brain differently through gut-brain nerve pathways, the type of fat you cook with could theoretically influence how much you eat at your next meal. Whether that effect is large enough to matter in humans eating mixed meals remains unknown.