Can I Drink Olive Oil at Night? Benefits and Risks

Drinking a small amount of olive oil at night is safe for most people and may offer digestive and cardiovascular benefits, but the timing creates a specific risk: acid reflux. Fat slows stomach emptying, and lying down soon after swallowing any calorie-dense liquid can push stomach contents back toward the esophagus. Whether the practice helps or hurts you depends largely on how much you drink, how soon you go to bed afterward, and whether you already deal with heartburn or gallbladder issues.

How Olive Oil Behaves in Your Stomach

When you swallow a tablespoon or two of olive oil, your stomach treats it the way it treats any fat: it slows down. Fat triggers a set of hormonal signals that tell the stomach to take its time, releasing its contents into the small intestine gradually rather than all at once. In a study of people with type 2 diabetes, consuming olive oil before a carbohydrate meal markedly slowed gastric emptying and delayed the rise in blood sugar compared to eating the same meal with water alone.¹ This sluggish emptying is why olive oil feels heavier than you might expect from just a tablespoon of liquid.

That slowdown is useful when you want to blunt a blood sugar spike after dinner. But at night, the same mechanism works against you if you plan to lie down within the next hour or two. A stomach that is still slowly processing fat is a stomach that is more likely to let acid creep upward when you shift to a horizontal position. The issue is not that olive oil is uniquely problematic; any concentrated source of fat creates the same delay.

The Acid Reflux Risk

This is the main practical concern with drinking olive oil close to bedtime. An evidence-based consensus on reflux management found that leaving less than three hours between an evening meal and going to bed increased the odds of reflux symptoms roughly sevenfold compared to waiting four hours or more.² A separate systematic review confirmed that eating within two to three hours of bedtime and consuming high-fat foods are both independently associated with gastroesophageal reflux disease.³

Olive oil is pure fat. If you drink it right before climbing into bed, you are combining two of the strongest reflux triggers at once: a high-fat intake and a short dinner-to-bed interval. People who already experience heartburn, nighttime regurgitation, or a sour taste in the mouth on waking should be especially cautious. The simple fix is timing. If you want to drink olive oil in the evening, do it at least three hours before you plan to lie down. That gives your stomach enough time to move the oil along and reduces the reflux window considerably.

Constipation Relief, Especially from Extra Virgin

One of the most common reasons people drink olive oil at night is to ease constipation, with the idea that the oil will work overnight and produce results the next morning. There is decent evidence that this actually works. A double-blind trial comparing extra virgin olive oil to refined olive oil over four weeks found that both reduced constipation symptom scores, but extra virgin olive oil was substantially more effective. Stool consistency scores improved week after week in the extra virgin group, with the gap widening over time.⁴

Another trial, this one in hemodialysis patients who commonly suffer from constipation, found that daily olive oil performed as well as mineral oil, the traditional go-to laxative, in improving constipation symptoms.⁵ A systematic review of over-the-counter constipation remedies noted olive oil among the agents that significantly reduced constipation symptom frequency.⁶

The mechanism is straightforward: oil lubricates the intestinal tract and stimulates bile secretion, both of which help move stool along. The extra polyphenols in extra virgin olive oil likely add an additional effect by influencing gut motility and the intestinal environment in ways that refined oil cannot. If constipation is your reason for trying this, the evidence favors extra virgin over cheaper refined versions, and a tablespoon or two in the evening is a reasonable dose. Just keep the three-hour reflux buffer in mind.

Blood Sugar Effects Worth Knowing About

If you eat dinner and then drink olive oil as a sort of nightcap, or if you take the oil before your evening meal, the fat changes how your body handles the carbohydrates in that meal. Research in people with type 2 diabetes showed that when olive oil was consumed before a carbohydrate-rich meal, the postprandial blood sugar rise was markedly delayed, and insulin and glucose-dependent insulinotropic peptide responses were blunted. At the same time, the oil stimulated a greater release of GLP-1, a hormone that promotes satiety and helps regulate blood sugar.¹

A study in people with type 1 diabetes found that a meal prepared with extra virgin olive oil led to lower postprandial blood sugar than the same meal prepared with butter, with differences in how quickly the stomach emptied its contents accounting for much of the effect.⁷ For anyone managing blood sugar, especially at dinner when overnight glucose control matters, olive oil with or before the meal can smooth out the curve. This is less about drinking olive oil on its own and more about using it alongside carbohydrates you are already eating, but the principle applies either way.

What Olive Oil Does for Your Heart Over Time

The cardiovascular argument for olive oil does not depend on when you consume it, but it is part of why people adopt the evening ritual in the first place. The polyphenols in extra virgin olive oil appear to have meaningful effects on cholesterol markers. A randomized controlled trial in men found that high-polyphenol olive oil decreased the number of total and small LDL particles by about 12% and 15% respectively, while also increasing LDL oxidation lag time, a measure of how resistant LDL is to the oxidative damage that drives plaque formation.⁸

A crossover trial found that both low-polyphenol and high-polyphenol olive oil raised HDL cholesterol modestly from baseline, though the two oils did not differ from each other on that measure.⁹ The takeaway is that the polyphenol content of the oil matters for certain LDL benefits, but even lower-polyphenol olive oil nudges HDL in a favorable direction. If you are going to drink olive oil, choosing a high-quality extra virgin variety gets you more of the compounds that seem to do the most cardiovascular work.

One of those compounds, oleocanthal, has attracted particular research interest. It acts as a natural anti-inflammatory, and studies have confirmed that the human body absorbs and metabolizes it after consumption. Oleocanthal metabolites have been detected in urine, confirming its bioavailability.¹⁰ Oleocanthal is the compound responsible for the peppery throat sting you feel with a good extra virgin oil. That sting is actually a rough indicator of polyphenol content: the more it burns, the more oleocanthal is present.

Does Your Body Handle Fat Differently at Night?

This is a question that matters for the “should I drink it at night specifically?” angle, and the honest answer is that the research is thin and somewhat inconsistent. A systematic review of studies comparing nighttime versus daytime meals found that most studies identified at least one parameter of the postprandial triglyceride response that differed depending on when the meal was eaten. Two studies reported higher total triglyceride concentrations after nighttime eating, while three others found no difference. Several studies found that the time-course pattern of triglyceride clearance shifted at night, even when the total amount stayed similar.¹¹

The review’s conclusion was cautious: nighttime eating may negatively affect how your body processes circulating fats, but the evidence is not yet strong enough to make firm recommendations. The studies varied widely in design, sample sizes were small, and the methods used to measure triglycerides were not standardized. What seems plausible, though not proven beyond doubt, is that your body’s fat-clearing machinery works a bit less efficiently at night, which would mean that fat consumed late in the evening lingers in your bloodstream slightly longer than the same fat eaten at lunch. For a single tablespoon of olive oil, this is probably a negligible difference. For a large, high-fat evening meal, it could be more relevant.

The Gallbladder Factor

When fat enters your digestive system, your gallbladder contracts to release bile. Olive oil is a potent trigger for this contraction. Research has shown that oral olive oil causes significant gallbladder contraction, though the response is somewhat slower and less forceful when the oil enters through the mouth compared to being delivered directly into the upper small intestine.¹² For most people, this is unremarkable. Your gallbladder contracts every time you eat fat; that is its job.

But if you have gallstones, particularly stones that are borderline large enough to obstruct the bile duct, a strong gallbladder contraction can trigger a gallbladder attack. These attacks are classically described as severe pain in the upper right abdomen, often occurring at night after a fatty meal. Drinking concentrated fat like olive oil before bed is exactly the scenario that could provoke one. If you have known gallstones, have had your gallbladder removed, or have experienced unexplained upper abdominal pain after fatty meals, check with your doctor before adopting an evening olive oil habit.

How Much Should You Actually Drink?

Most of the clinical trials that have shown benefits used doses ranging from about one to three tablespoons per day, which translates to roughly 15 to 45 milliliters. A single tablespoon of olive oil contains about 120 calories and 14 grams of fat. That is a meaningful caloric addition if you are watching your weight, but it is also a modest one, equivalent to a large handful of nuts.

A trial in women with excess body fat found that adding extra virgin olive oil to the diet over a controlled period led to about 80% more fat loss compared to a soybean oil control group, suggesting that the type of fat matters more than the raw calorie count.¹³ That said, olive oil is still calorie-dense. Drinking three tablespoons on top of your normal diet without cutting back anywhere else adds about 360 calories per day, which over time would lead to weight gain regardless of the oil’s metabolic benefits. One to two tablespoons is a reasonable nighttime dose for most people, ideally replacing rather than adding to other fats in your diet.

Olive Oil and Sleep Quality

Some proponents of the nighttime olive oil ritual claim it improves sleep. The direct evidence for this specific claim is weak, but the indirect evidence is interesting. A review of the relationship between Mediterranean diet adherence and sleep found that people who more closely followed a Mediterranean-style eating pattern, which prominently features olive oil, tended to report better sleep quality and more adequate sleep duration.¹⁴ The proposed mechanisms involve the anti-inflammatory and antioxidant properties of Mediterranean foods, as well as their effects on serotonin and melatonin precursors.

The problem with drawing a straight line from “olive oil at bedtime” to “better sleep” is that the studies look at the entire dietary pattern, not a single ingredient consumed at a specific time. People who eat a Mediterranean diet also eat more fish, vegetables, legumes, and whole grains, and less processed food. Attributing their sleep improvements to a tablespoon of olive oil at 9 p.m. would be a stretch. What can be said is that olive oil is a reasonable part of a dietary pattern linked to better sleep, not that it works as a standalone sleep aid.

The Gut Microbiome Angle

Olive oil polyphenols interact with gut bacteria in ways that may amplify their health effects. A trial that tested virgin olive oil enriched with thyme phenolic compounds found that the enriched oil increased bifidobacteria numbers and raised levels of protocatechuic acid, a phenolic metabolite, compared to standard virgin olive oil. The enriched oil also reduced oxidized LDL.¹⁵ Standard virgin olive oil on its own did not produce the same microbial shifts, though it did increase certain fecal phenolic acid levels compared to baseline.

This suggests that the polyphenol content of the oil is critical for microbiome effects, and that pairing olive oil with other polyphenol-rich foods could amplify the benefit. If you are drinking olive oil at night partly for gut health, the quality of the oil matters, and so does the rest of your diet. A tablespoon of refined olive oil from a plastic jug is not going to deliver the same microbial effects as a high-polyphenol extra virgin oil.

Oil Pulling Before Bed

A practice adjacent to drinking olive oil at night is using it as a mouthwash, or “oil pulling,” before bed. This tradition has roots in Ayurvedic medicine, and recent clinical trials have tested it with olive oil specifically. A study in pediatric dental patients found that swishing with extra virgin olive oil daily for a month led to significant reductions in plaque and gingivitis scores.¹⁶ Another trial had gingivitis patients perform a five-minute rinse with extra virgin olive oil after brushing and flossing before bed for 30 days, and the researchers observed improvements in gingival health markers.¹⁷

Oil pulling is not a substitute for brushing and flossing, and the studies are still small. But if you already have olive oil as part of your evening routine, swishing a teaspoon around your mouth for a few minutes before spitting it out (not swallowing, since the point is to trap bacteria) is a low-risk addition. The polyphenols in extra virgin olive oil appear to have antimicrobial properties that complement mechanical cleaning. It is worth noting that you would spit this oil out rather than swallow it, so oil pulling and drinking olive oil are two separate practices that happen to share an ingredient and a time of day.

Who Should Skip the Nighttime Olive Oil

Most healthy adults can drink a tablespoon or two of olive oil in the evening without trouble, but certain groups should think twice. People with active reflux disease or frequent heartburn are taking on unnecessary risk by adding concentrated fat to their nighttime routine, even with a three-hour buffer. The fat load slows stomach emptying and increases the chance of acid escaping the stomach during sleep. People with gallstones or a history of gallbladder attacks should avoid large single doses of any fat, olive oil included, because the resulting gallbladder contraction can push a stone into the bile duct. And people who are calorie-conscious should account for the 120 calories per tablespoon rather than treating olive oil as metabolically free just because it is a “healthy fat.”

Children, pregnant women, and anyone on blood-thinning medication should also exercise some caution. Olive oil has mild antiplatelet effects at high doses, and while a tablespoon is unlikely to cause a clinical problem, combining it with anticoagulant drugs at higher doses is worth discussing with a pharmacist or physician. For most other people, though, a modest evening dose of high-quality extra virgin olive oil is one of the more benign health habits you could adopt, as long as you respect the reflux window and do not treat it as a cure-all.