Study Confirms Olive Oil's Role in Weight Management

Summary

A recent research review in the American Journal of Clinical Nutrition found that con­sum­ing seven grams of olive oil daily was asso­ci­ated with reduced weight gain over time, while other fats were linked to weight gain, accord­ing to data from 121,119 par­tic­i­pants in three stud­ies over three decades. Despite con­cerns about calo­rie den­sity and weight gain, the review under­scores the advan­tages of olive oil as a health­ier fat choice in weight man­age­ment, though chal­lenges remain in inter­pret­ing its role in the U.S. due to label­ing and dietary dif­fer­ences.

A recent research review pub­lished in the American Journal of Clinical Nutrition has con­firmed evi­dence sup­port­ing olive oil as a health­ier fat choice in weight man­age­ment. 

An inter­na­tional team of researchers led by the Harvard T.H. Chan School of Public Health ana­lyzed data from 121,119 par­tic­i­pants in the Nurses’ Health Study, the Nurses’ Health Study II, and the Health Professionals Follow-up Study to exam­ine the long-term effects of dietary fats on weight over a three-decade period.

While olive oil is widely cel­e­brated for its pos­i­tive effects on car­dio­vas­cu­lar dis­ease, con­cerns have lin­gered about its calo­rie den­sity and poten­tial to con­tribute to weight gain. 

However, the research review showed that con­sum­ing seven grams of olive oil daily was asso­ci­ated with reduced weight gain over time, while other types of edi­ble fats were linked to weight gain.

“A long-term increase in olive oil intake was inversely asso­ci­ated with body weight in mid­dle-aged adults in the United States,” the researchers wrote. ​“Conversely, increased con­sump­tion of other added fats, such as but­ter and mar­garine, was pos­i­tively asso­ci­ated with body weight.”

The find­ings held steady across var­i­ous age groups and base­line body mass indices, under­scor­ing the advan­tages of olive oil as a dietary fat.

However, the review also high­lights chal­lenges in inter­pret­ing the role of olive oil in weight man­age­ment, par­tic­u­larly in the United States. 

“It is very hard, if not impos­si­ble, in the U.S. to deter­mine what peo­ple are using for olive oil,” Mary Flynn, a nutri­tion researcher at Brown University, told Olive Oil Times. ​“It could be labeled ​‘extra vir­gin,’ but you would­n’t know if it had phe­nols, which account for the health ben­e­fits of extra vir­gin olive oil.” 

“Therefore, you can­not defin­i­tively say that the form of extra vir­gin olive oil with health ben­e­fits led to a decrease in body weight over time,” she added.

Flynn also pointed out that the study con­trolled for fac­tors such as diet qual­ity and changes in fruit and veg­etable intake. Still, it did not report changes in olive oil intake in rela­tion to total veg­etable con­sump­tion or veg­eta­bles alone. 

“I can’t help but think that some­one using olive oil, espe­cially in the U.S., is a ​‘dif­fer­ent’ per­son com­pared to some­one using veg­etable seed oils,” she said.

“Vegetable seed oils are often found in mar­garine, fried foods and may­on­naise, which are not typ­i­cally part of a healthy diet,” Flynn added. ​“Olive oil use may increase veg­etable con­sump­tion com­pared to seed oils or but­ter, as it is often used for sal­ads and veg­eta­bles.”

Flynn’s own research sup­ports the ben­e­fits of olive oil con­sump­tion for weight man­age­ment. 

“I believe I pub­lished the first study show­ing that women who were breast can­cer sur­vivors lost more weight with my plant-based olive oil diet, which included three table­spoons of extra vir­gin olive oil per day, com­pared to a lower-fat diet rec­om­mended by the National Cancer Institute,” she said. ​“More women chose it for six months of fol­low-up, indi­cat­ing higher accept­abil­ity.”

The research review builds on pre­vi­ous find­ings related to olive oil con­sump­tion and weight gain.

The PREDIMED (Prevention with Mediterranean Diet) cohort, a large Spanish clin­i­cal trial designed to inves­ti­gate the Mediterranean diet​’s effects on car­dio­vas­cu­lar health, ​“showed that higher olive oil intake in the con­text of an unre­stricted caloric Mediterranean diet was not asso­ci­ated with weight gain or higher waist cir­cum­fer­ence.”

Another study found that olive oil with a phe­nol con­tent higher than 366 mil­ligrams per kilo­gram led to bet­ter weight loss out­comes than refined olive oil (2.7 mil­ligrams per kilo­gram). 

Furthermore, research com­par­ing diets with olive oil and soy­bean oil showed sim­i­lar weight loss but more sig­nif­i­cant fat loss with olive oil, as mea­sured by dual-energy X‑ray absorp­tiom­e­try (DEXA) scans of body com­po­si­tion.

The socioe­co­nomic con­text also plays a role. The research review’s authors noted that olive oil intake in higher socioe­co­nomic classes may cor­re­late with veg­etable con­sump­tion, which could con­tribute to weight loss. 

However, Flynn’s work has shown that a plant-based olive oil diet can yield pos­i­tive out­comes even in lower socioe­co­nomic set­tings. 

“I pub­lished a study show­ing that a cook­ing pro­gram fea­tur­ing my plant-based olive oil recipes in food pantry clients resulted in weight loss over six months, despite no nutri­tion edu­ca­tion in the pro­gram,” she said. ​“It also led to increased veg­etable intake and improved food secu­rity.”

• Nutrients