Blasbalg, T. L., Hibbeln, J. R., Ramsden, C. E., Majchrzak, S. F., & Rawlings, R. R. (2011). Changes in consumption of omega-3 and omega-6 fatty acids in the United States during the 20th century. The American Journal of Clinical Nutrition, 93(5), 950-962. Apparent linoleic acid intake rose substantially across the 20th century, primarily from soybean oil. US food-disappearance data 1909-1999: soybean oil consumption rose more than 1000-fold; linoleic acid availability rose from 2.79% to 7.21% of energy and ALA from 0.39% to 0.72%; the LA:ALA ratio rose from 6.4 to 10.0; estimated omega-3 index fell from 6.51-8.28 to 3.84 (abstract, PMID 21367944). 10.3945/ajcn.110.006643
Johnson, G. H., & Fritsche, K. (2012). Effect of dietary linoleic acid on markers of inflammation in healthy persons: a systematic review of randomized controlled trials. Journal of the Academy of Nutrition and Dietetics, 112(7), 1029-1041. Across 15 RCTs in healthy non-infant adults, altering dietary linoleic acid produced virtually no change in inflammatory markers (CRP, fibrinogen, PAI-1, cytokines, soluble adhesion molecules, TNF-α). 10.1016/j.jand.2012.03.029
Mozaffarian, D., Micha, R., & Wallace, S. (2010). Effects on coronary heart disease of increasing polyunsaturated fat in place of saturated fat: a systematic review and meta-analysis of randomized controlled trials. PLoS Medicine, 7(3), e1000252. Replacing saturated fat with polyunsaturated fat reduced CHD events ~19% (RR 0.81, 95% CI 0.70-0.95), ~10% per 5% energy. 10.1371/journal.pmed.1000252
Hooper, L., Al-Khudairy, L., Abdelhamid, A. S., Rees, K., Brainard, J. S., Brown, T. J., et al. (2018). Omega-6 fats for the primary and secondary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews, (11), CD011094. Increasing omega-6 fats made little or no difference to cardiovascular events or mortality (low-certainty evidence), with a possible small reduction in myocardial infarction. 10.1002/14651858.CD011094.pub3
Alvheim, A. R., Malde, M. K., Osei-Hyiaman, D., Lin, Y. H., Pawlosky, R. J., Madsen, L., et al. (2012). Dietary linoleic acid elevates endogenous 2-AG and anandamide and induces obesity. Obesity, 20(10), 1984-1994. In mice, raising dietary linoleic acid from 1% to 8% of energy tripled the endocannabinoids 2-AG and anandamide, increasing food intake and adiposity; adding EPA/DHA reversed it. Animal model — not yet demonstrated in humans. 10.1038/oby.2012.38
Hall, K. D., Ayuketah, A., Brychta, R., Cai, H., Cassimatis, T., Chen, K. Y., et al. (2019). Ultra-processed diets cause excess calorie intake and weight gain: an inpatient randomized controlled trial of ad libitum food intake. Cell Metabolism, 30(1), 67-77.e3. 20 inpatients, 2 weeks per diet, crossover. Meal eating rate was greater on the ultra-processed diet by 17 +/- 1 kcal/min (7.4 +/- 0.9 g/min), p < 0.0001 - that is the between-diet difference; ratings of pleasantness and familiarity did not differ (full text, PMC7946062). Diets were matched for presented calories, energy density including beverages (1.024 vs 1.028 kcal/g), macronutrients, sugar, sodium and fiber (21.3 vs 20.7 g/1000 kcal, partly via fiber supplements added to ultra-processed meals); non-beverage energy density was 1.957 vs 1.057 kcal/g (~85% higher), which the authors say likely contributed. Intake was 508 +/- 106 kcal/day greater on the ultra-processed diet (full text, Table 1 and Results). 10.1016/j.cmet.2019.05.008