Study is among the largest to date to examine the relationship between omega-6 fatty acids and adiposity using objective blood biomarkers
June 11, 2026, Sioux Falls, SD: A new large-scale study published by researchers affiliated with the Fatty Acid Research Institute (FARI) and OmegaQuant Analytics provides compelling evidence that higher levels of linoleic acid (LA)—the most abundant omega-6 fatty acid in the diet—are associated with lower body weight, smaller waist circumference, and reduced body fat.
Published in the British Journal of Nutrition, the study analyzed data from more than 272,000 participants in the UK Biobank, and is among the largest to date to examine the relationship between omega-6 fatty acids and adiposity using objective blood biomarkers.
The study, “Omega-6 Polyunsaturated Fatty Acids and Adiposity in the UK Biobank Cohort,” evaluated both cross-sectional and longitudinal associations between circulating omega-6 fatty acids and measures of adiposity, including weight, waist circumference, and whole-body fat mass.
Across both cross-sectional and longitudinal analyses, individuals with higher circulating LA levels consistently demonstrated more favorable body composition, including lower weight and fat mass over time. For example, in the cross-sectional analysis, participants in the highest quintile of LA weighed on average approximately 26 pounds less than participants in the lowest quintile. In contrast, other non-LA omega-6 fatty acids showed small associations in the opposite direction—highlighting the importance of distinguishing between different types of omega-6s rather than treating them as a single category.
“These findings are important because they directly challenge the narrative that omega-6 fats—especially those found in seed oils—are driving obesity,” said William S. Harris, PhD, founder of OmegaQuant, President of FARI, and co-author on the study. “When you actually measure what’s in the blood, higher levels of linoleic acid are linked to better, not worse, body composition.”
The results add to a growing body of evidence supporting the role of LA-rich foods—such as vegetable oils, nuts, and seeds—as part of a healthy diet. They also reinforce the value of using biomarker-based assessments rather than dietary recall to better understand how nutrients impact health outcomes.
“Not all omega-6 fatty acids behave the same way in the body,” Dr. Harris added. “This study shows why it’s critical to move beyond oversimplified messaging and focus on the specific fatty acids that are actually associated with positive health outcomes, like LA.”
As obesity rates continue to rise globally, the findings provide important new insight into how dietary fats influence body composition—and underscore the need for more nuanced, evidence-based nutrition guidance.
Disclaimer:
This publication from FARI was partially funded by Soy Nutrition Institute Global, with support from the United Soybean Board, neither of which had any input into the study design, data analysis or interpretation.
