`Study Finds Oleic Acid in Diet Linked to Obesity - Olive Oil Times
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Study Finds Oleic Acid in Diet Linked to Obesity

By Paolo DeAndreis
Jul. 1, 2025 19:42 UTC
Summary Summary

A study pub­lished in Cell Reports sug­gests that oleic acid, found in foods like olive oil, may stim­u­late the pro­lif­er­a­tion of fat cells in humans, poten­tially con­tribut­ing to obe­sity. While the study did not exam­ine the impact of olive oil specif­i­cally, other research has shown that increased con­sump­tion of olive oil is linked to reduced weight gain and improved meta­bolic health, sup­port­ing its use in long-term dietary strate­gies. Oleic acid from plant-based sources like olive oil may pro­mote weight man­age­ment by enhanc­ing sati­ety and energy expen­di­ture with­out con­tribut­ing to weight gain, con­trast­ing with MUFAs from ani­mal sources.

A new study sug­gests that a diet high in oleic acid may stim­u­late the pro­lif­er­a­tion of spe­cific fat cells that are des­tined to per­sist for years in humans.

The research, con­ducted by sev­eral promi­nent U.S. uni­ver­si­ties and pub­lished in Cell Reports, screened a vari­ety of com­monly con­sumed dietary fats.

It found that oleic acid is the only fatty acid capa­ble of induc­ing obe­so­genic hyper­pla­sia at phys­i­o­log­i­cal lev­els.

If you look at the fig­ures, they did not test olive oil. Oleic acid may, on a cel­lu­lar level, increase adipocyte pro­duc­tion more than other fatty acids, but since they did not test olive oil, refined or extra vir­gin, it is not an issue for olive oil.- Mary Flynn, asso­ciate pro­fes­sor of med­i­cine, Brown University

Hyperplasia is the process by which tis­sue expands through an increase in the num­ber of its cells. In the con­text of obe­sity, this means a grow­ing num­ber of fat cells, not just an increase in their size, can lead to last­ing weight gain and dif­fi­cult-to-reverse meta­bolic changes.

Oleic acid is nat­u­rally present in many foods, includ­ing olive oil, canola oil, avo­cado oil and var­i­ous nuts and seeds. It is also found in ani­mal fats.

The Food and Drug Administration has sup­ported health claims for oleic acid, cit­ing its role in reduc­ing the risk of coro­nary heart dis­ease.

See Also:Health News

In recent years, many U.S. food man­u­fac­tur­ers have added oleic acid to processed foods, and some veg­etable oils have been mod­i­fied to sig­nif­i­cantly increase their oleic acid con­tent.

According to the study, plasma lev­els of monoun­sat­u­rated fatty acids (MUFAs), mostly oleic acid, are asso­ci­ated with obe­sity in humans.

Using data from the United Kingdom Biobank, a long-term health data­base of more than 500,000 indi­vid­u­als, researchers exam­ined 249 plasma bio­mark­ers.

Among all of them, MUFAs had the high­est haz­ard ratio for over­weight and obe­sity sta­tus. In other words, indi­vid­u­als with higher MUFA lev­els, par­tic­u­larly oleic acid, in their blood were sig­nif­i­cantly more likely to be obese.

These find­ings sup­port pre­vi­ous mouse stud­ies in which dietary oleic acid increased both plasma oleic acid and the for­ma­tion of new fat cells.

The study sug­gests that ele­vated lev­els of cir­cu­lat­ing oleic acid may con­tribute to obe­sity by pro­mot­ing the pro­lif­er­a­tion of adipocyte pre­cur­sor cells and the cre­ation of new fat cells.

However, the study did not exam­ine the dietary impact of olive oil.

“In the past, it was very com­mon to dis­cuss nutri­ents. My inter­est in olive oil led me to real­ize one needed to dis­cuss food sources of the nutri­ent, not the nutri­ent itself,” said Mary Flynn, asso­ciate pro­fes­sor of med­i­cine and clin­i­cal edu­ca­tor at Brown University, who was not involved in the study.

“If you look at the fig­ures, they did not test olive oil,” she added. ​“Oleic acid may, on a cel­lu­lar level, increase adipocyte pro­duc­tion more than other fatty acids, but since they did not test olive oil, refined or extra vir­gin, it is not an issue for olive oil.” 

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More broadly, Flynn crit­i­cized the use of Mediterranean diet scores in research conducted in coun­tries where olive oil is not the pri­mary source of dietary fat.

“I think stud­ies using the Med Diet score are some­what worth­less, unless the whole pop­u­la­tion is in an olive oil-con­sum­ing coun­try,” she said.

“In stud­ies con­ducted in most parts of the world, monoun­sat­u­rated fat comes from beef and veg­etable seed oils. So it’s no sur­prise that stud­ies inves­ti­gat­ing the ratio of MUFA to sat­u­rated fats sel­dom show ben­e­fit [from oleic acid con­sump­tion],” Flynn noted, point­ing to the diver­sity of oleic acid sources.

The U.K. Biobank, while an impres­sive data resource, includes only par­tic­i­pants from England, Scotland and Wales. In these coun­tries, olive oil is not a pri­mary dietary fat.

See Also:Study Reveals Insights Into the Impact of Olive Oil Fats on Essential Cell Structures

Interestingly, other long-term stud­ies have shown that olive oil may sup­port healthy weight man­age­ment even in non-Mediterranean pop­u­la­tions.

A recent paper pub­lished in the American Journal of Clinical Nutrition found that increased con­sump­tion of olive oil is asso­ci­ated with reduced long-term weight gain.

Researchers from Harvard and other insti­tu­tions fol­lowed more than 121,000 American adults for up to 24 years across three major cohort stud­ies (Nurses’ Health Study, NHS II and the Health Professionals Follow-up Study).

They found that for every addi­tional half table­spoon (approx­i­mately seven grams) of olive oil con­sumed daily, par­tic­i­pants lost 0.09 kilo­grams every four years.

In con­trast, increased intake of added fats, such as but­ter and mar­garine, as well as com­mon veg­etable oils like soy­bean and canola, was asso­ci­ated with greater weight gain.

Even in a pop­u­la­tion where olive oil is not a dietary sta­ple, its ben­e­fits emerged. Substitution analy­ses revealed that replac­ing equal amounts of but­ter, mar­garine, or other fats with olive oil con­sis­tently resulted in less weight gain.

Swapping seven grams of but­ter with olive oil, for instance, resulted in nearly 0.5 kilo­grams less weight gain every four years.

Other research has also found that plant-derived MUFAs, such as those found in olive oil, nuts, and seeds, are linked to lower mor­tal­ity and a reduced risk of car­dio­vas­cu­lar dis­ease and type 2 dia­betes.

In con­trast, MUFAs from ani­mal sources, includ­ing meat, dairy, and eggs, showed neu­tral or neg­a­tive asso­ci­a­tions with these out­comes.

According to Harvard researchers, oleic acid may aid in weight man­age­ment by enhanc­ing sati­ety, increas­ing energy expen­di­ture, and stim­u­lat­ing ther­mo­ge­n­e­sis, all of which con­tribute to a health­ier energy bal­ance.

Unlike sat­u­rated fats or ani­mal-derived MUFAs, plant-based oleic acid appears to pro­mote meta­bolic health with­out con­tribut­ing to weight gain.

The researchers also high­lighted the pos­si­bil­ity that olive oil’s com­bi­na­tion of oleic acid and bioac­tive com­pounds could help reduce abdom­i­nal fat and influ­ence appetite-reg­u­lat­ing mech­a­nisms, mak­ing it a valu­able com­po­nent in long-term dietary strate­gies.

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