Omega-3 fatty acids (fish oil) & Obesity

Written based on 31 research studies on PubMed, searched on 2026. nov. 11..

The claim

Posts online say that omega-3 fatty acids (fish oil) helps with obesity.

Where research stands

We found 516 published papers on omega-3 fatty acids (fish oil) and obesity. They were published between 1990 and 2026. 118 of them are studies in people. 108 of them compared people who got it with a group that did not. 231 were studies in animals, and 6 were only in cells in the lab. 58 papers are reviews that sum up other studies. 1 paper was retracted. 5 new studies in people are running or will start soon, say the trial registers.

• 118In people108 with a comparison group
• 231In animals
• 6Only in the lab

What the studies found

We have not summed up these studies in words yet. The most important papers are listed under Sources.

Verdict

Sources

1. Effects of Omega-3 and Omega-9 Fatty Acid Supplementation on HOMA-IR and Inflammatory Markers in Children with Obesity and Insulin Resistance: A Triple-Blind RCT with Post-Intervention Follow-Up.2026 · Nutrients · Randomised trial
2. Weight Loss and Omega-3 Supplementation Modulate the Microbiome in Women with Increased Breast Cancer Risk.2026 · Cancer Prev Res (Phila) · Randomised trial
3. Combined effectiveness of omega-3 PUFA-rich fish oil supplementation and high-intensity interval training in obesity associated metabolic dysfunction: Protocol for a double-blind, randomized clinical trial.2026 · Contemp Clin Trials · Randomised trial
4. Study Protocol and Baseline Cardiometabolic Characterization of the RIO-Study (Response to an Intervention with Omega-3): A Randomized, Double-Blind, Placebo-Controlled Crossover Trial on Lipid and Inflammatory Profiles in Overweight and Obese Adults with Hypertriglyceridemia in Valdivia, Chile.2025 · Nutrients · Randomised trial
5. Effect of a Diet Supplemented with Marine Omega-3 Fatty Acids on Inflammatory Markers in Subjects with Obesity: A Randomized Active Placebo-Controlled Trial.2025 · Healthcare (Basel) · Randomised trial
6. FADS1 Genetic Variant and Omega-3 Supplementation Are Associated with Changes in Fatty Acid Composition in Red Blood Cells of Subjects with Obesity.2024 · Nutrients · Randomised trial
7. Growth patterns in infants born to women with pregestational overweight/obesity supplemented with docosahexaenoic acid during pregnancy.2024 · J Pediatr Gastroenterol Nutr · Randomised trial
8. Effects of Omega-3 Supplementation on the Delayed Onset Muscle Soreness after Cycling High Intensity Interval Training in Overweight or Obese Males.2024 · J Sports Sci Med · Randomised trial
9. Weight loss induced by a hypocaloric diet with or without fish oil supplementation re-established iron and omega-3 fatty acid homeostasis in middle-aged women with obesity: A post-hoc analysis of a randomized controlled trial.2024 · Maturitas · Study in people
10. The impact of fish oil and/or probiotics on serum fatty acids and the interaction with low-grade inflammation in pregnant women with overweight and obesity: secondary analysis of a randomised controlled trial.2024 · Br J Nutr · Study in people
11. Omega-6 and omega-3 fatty acids in feeding behavior: Biological mechanisms and implications for dietary adherence. A mini-review.2026 · Neurosci Biobehav Rev · Review
12. Neuroinflammation in Alzheimer's Disease: The Role of Obesity, Gut Microbiota, and Therapeutic Potential of Omega-3 Fatty Acids and Neural Stem Cells.2026 · J Nutr · Review
13. Effects of Omega-3 Fatty Acids on High-Fat Diet-Induced Obesity: A Systematic Review of Rodent Studies.2026 · Nutr Rev · Review
14. Omega-3 supplementation and cardiometabolic risk factors in obese/overweight children and adolescents: a GRADE assessed systematic review and meta-analysis.2025 · Nutr Metab (Lond) · Review
15. Interaction between dietary omega-3 polyunsaturated fatty acids, obesity and gut microbiota in preclinical models: A systematic review of randomized controlled trials.2025 · Diabetes Obes Metab · Review
16. Omega-3 Fatty Acids and Exercise in Obesity Management: Independent and Synergistic Benefits in Metabolism and Knowledge Gaps.2025 · Biology (Basel) · Review
17. Transgenic Conversion of Omega-6 to Omega-3 Fatty Acids via fat-1 Reduces Obesity-Related Intervertebral Disc Degeneration.2026 · JOR Spine · In animals
18. Fish oil and evening primrose oil have ameliorative effects on obesity-associated complications in olanzapine-administered rats.2026 · Obes Res Clin Pract · In animals
19. Nutritional characterization of Cusco green tea and its synergistic effect with omega-3 on metabolic and cognitive dysfunctions in obese rats.2026 · J Sci Food Agric · In animals
20. Fish Oil Alters the Metabolome, Antioxidative Potential, and Secretory Profile of Visceral Adipose Tissue in Mice with High-Fat Diet-Induced Obesity Compared with Other Dietary Fat Sources.2026 · Molecules · In animals
21. Omega-3 dietary supplementation combined with exercise to keep telomere integrity in the liver of aged obese female mice.2026 · J Physiol Biochem · In animals
22. Effects of Eicosapentaenoic Acid on the Glycerophosphate Shuttle-Regulated Inflammatory and Thermogenic Responses.2026 · Obesity (Silver Spring) · In animals
23. Omega-3 polyunsaturated fatty acids and epigallocatechin-3-gallate attenuate obesity-associated CD44-high stemness in colorectal cancer through modulation of Notch1, Wnt/β-catenin and PI3K/mTOR signaling.2026 · Biomed Pharmacother · In the lab
24. Effect of docosahexaenoic acid as an anti-inflammatory for Caco-2 cells and modulating agent for gut microbiota in children with obesity (the DAMOCLE study).2025 · J Endocrinol Invest · In the lab
25. Breast Milk from Non-Obese Women with a High Omega-6 to Omega-3 Fatty Acid Ratio, but Not from Women with Obesity, Increases Lipogenic Gene Expression in 3T3-L1 Preadipocytes, Suggesting Adipocyte Dysfunction.2022 · Biomedicines · In the lab
26. Omega-3 polyunsaturated fatty acids attenuate inflammatory activation and alter differentiation in human adipocytes.2019 · J Nutr Biochem · In the lab
27. RETRACTED: Cold-Pressed Nigella Sativa Oil Standardized to 3% Thymoquinone Potentiates Omega-3 Protection against Obesity-Induced Oxidative Stress, Inflammation, and Markers of Insulin Resistance Accompanied with Conversion of White to Beige Fat in Mice.2020 · Antioxidants (Basel) · RetractedRetracted
28. Adults with obesity and hyperglycemia have higher arachidonic and docosahexaenoic acid in subcutaneous adipose tissue.2026 · J Lipid Res · Other paper
29. Long-chain omega-3-enriched erythrocyte fatty acid pattern is associated with lower odds of obesity and metabolic dysfunction-associated steatotic liver disease.2026 · Nutr J · Other paper
30. Associations of Dietary Omega-3 and Omega-6 Fatty Acids, Obesity, and Psychological Stress with Fatigue in Patients with Chronic Obstructive Pulmonary Disease: A Cross-Sectional Study.2026 · Nutrients · Other paper
31. Omega-3 Long-Chain Polyunsaturated Fatty Acid Supplementation Did Not Reduce Inflammation to Improve Iron Absorption in South African Women Living with Overweight or Obesity.2026 · J Nutr · Other paper