Could olive oil shots in the morning actually have some scientific basis behind them? Although people mostly participate in this trend for its unproven “anti-aging” and “skin glow” benefits, touted on social media, consuming fats before carbohydrates may offer other health benefits, particularly for blood sugar management.
A recent study, published in the journal Diabetes, found that consuming olive oil before carbs can help blunt early spikes in blood sugar via several hormone and nerve pathways — at least in mice.
As part of their experiment, the researchers gave a group of mice olive oil 15 minutes before they conducted a glucose load test, commonly known as an Oral Glucose Tolerance Test (OGTT).
Another group of mice received a water preload before the glucose load, while a third group received olive oil after the glucose load. The researchers then compared blood sugar levels between all three groups.
The researchers observed that preloading with olive oil led to a smaller rise in blood sugar levels and delayed gastric emptying. This benefit was also seen in mice with type 2 diabetes and severe insulin deficiency.
They also observed earlier and more pronounced surges in gut and endocrine hormones, including glucagon, GIP (glucose-dependent insulinotropic polypeptide), and GLP-1 (glucagon-like peptide-1), in the group that received an olive oil preload. This happened within 15-30 minutes after eating.
These findings indicate that taking olive oil first — or consuming fats before carbs — can trigger gut hormones and nerve signals that slow down stomach digestion before the sugar arrives.
This slowdown can, therefore, prevent sugar from entering the bloodstream all at once, halting the post-meal blood sugar spike.
Senior author of this study, Daisuke Yabe, MD, a professor of medicine at Kyoto University in Japan, said in a press release:
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“The order in which nutrients reach the gut can engage a coordinated hormone-nerve response that changes how quickly the stomach delivers glucose to the intestine.”
Medical News Today spoke to three experts — Noah Praamsma, MS, RDN, nutrition education coordinator with the
Physicians Committee for Responsible Medicine, Jennifer Pallian, RD, specializing in food and nutrition science, and Edmundo Rodriguez-Frias, MD, gastroenterologist at Anderson Medical Group in Maryville, Illinois, to discuss the findings and whether olive oil shots have health risks.
In the study, the mice that received olive oil before carbs showed signs of slowed gastric emptying. Praamsma explained the process:
“Blood sugars rise when carbohydrates get absorbed in the small intestine. One way to blunt the rate of absorption is to slow down how quickly food moves from the stomach into the intestine, and consuming fat can do that. When fat, like olive oil, gets into the small intestine, it causes hormones like GLP-1 to be released that slow down how quickly food still in the stomach gets released into the intestine.”
Apart from delayed gastric emptying, the mice that consumed olive oil before glucose also showed increases in certain gut and endocrine hormones.
When asked how these hormones may help reduce blood sugar rises, Pallian explained: “GLP-1 and glucagon appear to work through partially overlapping pathways to slow gastric emptying, with the vagus nerve, which helps regulate gastrointestinal function, also playing a role.”
“Interestingly, these effects occurred without a substantial increase in insulin secretion, suggesting that slower gastric emptying, rather than increased insulin production, was primarily responsible for the improved blood sugar response,” she added.
“Consuming olive oil before carbohydrates may help regulate blood sugar by slowing gastric emptying, which is the rate at which food moves from the stomach into the small intestine. This delays glucose absorption and helps reduce the rise in blood sugar after eating.”
— Jennifer Pallian, MS, RDN
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Although this study was conducted in mice, similar effects have been observed in humans, too.
“In a small randomized crossover study involving six men with type 2 diabetes, consuming 30 mL [milliliters] of olive oil 30 minutes before a carbohydrate-rich meal significantly slowed gastric emptying, delayed the rise in blood glucose, and increased GLP-1 secretion compared with consuming water beforehand or incorporating olive oil into the meal,” Pallian said.
She also gave an example of a small study that found that eating fish or meat before rice helped delay gastric emptying and improve blood sugar responses.
“Together, these findings suggest that the order in which we consume foods may play an important role in blood sugar regulation,” she said.
One of the biggest limitations of the study is that it was conducted in animals, and similar results may not be seen in humans.
“[The] findings come from mice, so we cannot assume that consuming olive oil before carbohydrates will produce the same effects in humans. Although animal models are valuable for understanding biological mechanisms, they do not always accurately reflect the complex metabolic changes associated with human type 2 diabetes, particularly when diabetes is chemically induced as was done in this study,” Pallian said.
A smaller early spike in blood sugar also does not necessarily demonstrate improved insulin sensitivity or lasting effects on diabetes management.
Rodriguez-Frias underscored that the study leaves out many crucial components of diabetes management.
“[The study] cannot establish durable effects on HbA1c, weight, cardiovascular outcomes, or medication needs. The biggest limitation is that the study was conducted in mice using a controlled oral glucose load, not in people eating regular meals. Differences in digestion and metabolism mean the same effects may not occur in humans,” he noted.
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The amount of olive oil the researchers chose to give the mice was also quite a large dose, beyond what is typical consumption.
“[The] relatively large acute dose of olive oil used in the study, 5 mL per kilogram of body weight [may] not reflect typical dietary intake. These differences make it difficult to determine how directly the findings apply to people consuming smaller amounts of olive oil as part of their everyday diets,” Pallian pointed out.
Praamsma also underscored that slowing down gastric emptying does not change how much glucose the body absorbs, and said “it could cause a person’s peak blood sugar to come later when they aren’t expecting it.”
“Additionally, any type of oil is a concentrated source of calories and won’t help with long-term blood sugar management,” he added.
Consuming small shots of olive oil, often mixed with ingredients such as lemon juice, black pepper, or turmeric, has recently become a social media trend. However, evidence supporting this habit is currently lacking.
“There are currently no studies specifically examining the potential health risks of olive oil shots, but some of the ingredients may raise concerns. For instance, fresh lemon juice is highly acidic, and frequent exposure to dietary acids can contribute to dental erosion, a process in which tooth enamel gradually wears away,” said Pallian.
She went on to explain how acidic foods, especially when taken in the morning, can negatively affect health.
“Dental erosion occurs when acids cause the loss of minerals from the teeth, initially softening the enamel and eventually resulting in permanent loss of tooth structure. Research has identified acidic beverages, including fruit juices, as important contributors to dental erosion,” she said.
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Rodriguez-Frias also touched on the dangers of adding other ingredients into the mix, such as lemon juice and black pepper, saying it “may aggravate reflux in some people, while turmeric can also cause stomach upset.”
“There is no good evidence that adding these ingredients makes olive oil shots more effective for blood sugar control,” he said.
Rodriguez-Frias elaborated further on the gastrointestinal effects of olive oil shots:
“An olive oil shot delivers concentrated fat quickly, which may cause nausea, cramping, loose stools, or worsen reflux in some people. Be sure to pay close attention to your body, as some people with delicate digestive systems find that consuming anything too oily or acidic on an empty stomach can cause gastrointestinal distress.”
The caloric content of olive oil shots may be another concern for some people.
“[O]live oil is calorie-dense, meaning that even relatively small amounts can contribute a substantial number of calories to the diet. Adding a daily olive oil shot without adjusting calorie intake from other foods and beverages could increase overall calorie consumption, which may be counterproductive for people trying to lose weight,” Pallian said.
“Each tablespoon of olive oil has 120 calories, all of which come from fat. It doesn’t contain fiber, or any other type of carbohydrate, or protein. Those 120 calories could contribute to weight gain if part of an overall caloric surplus,” Praamsa continued.
Pallian added that olive oil does not have to be consumed separately from meals to provide health benefits.
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Regarding consuming olive oil every day, the experts agreed on its health benefits, particularly for cardiovascular health.
“Olive oil is rich in monounsaturated fatty acids, especially oleic acid, and contains beneficial compounds such as vitamin E and polyphenols, which contribute to its antioxidant and anti-inflammatory properties. These compounds may help explain why olive oil consumption has been linked to improvements in several cardiovascular and metabolic health markers, including cholesterol levels, blood pressure, insulin sensitivity, blood sugar regulation, and inflammation,” Pallian told us.
Rodriguez-Frias noted a 2022 study, published in the Journal of the American College of Cardiology (JACC), that found that consuming more than 7 grams (g) of olive oil daily reduced mortality.
The same study also found that replacing fats such as butter, margarine, or mayonnaise with olive oil was associated with an 8–34% lower risk of all-cause mortality.
Rodriguez-Frias cautioned against overinterpreting these findings.
“It does not prove that one to two tablespoons taken alone causes the benefit. Of course, olive oil is still a calorie-dense food, so your best bet is to use it to replace less healthy fats in your diet,” he said.
Meanwhile, Praamsa gave examples of other foods that may help soften blood sugar spikes: “[T]here are other foods that can also blunt the risk [of high] blood sugar after a meal. Beans and other legumes, non-starchy vegetables, and plant foods rich in protein and fiber like soy (tofu, tempeh, edamame, etc.) can also have the same effect, and will help with long-term blood sugar control, too.”
“While the evidence supports regularly incorporating olive oil into a healthy diet, particularly as a replacement for certain other fats, there is no established additional benefit to consuming 1–2 tablespoons as a standalone daily shot rather than using the same amount in meals.”
— Jennifer Pallian, MS, RDN
