Scientists at the University of California, Riverside, have found that soybean oil may contribute to obesity mainly due to molecules called oxylipins, which are formed from the metabolism of linoleic acid, the main component of soybean oil[1][2]. Oxylipins promote inflammation, increase fat in the liver and alter the function of genes linked to metabolism, leading to weight gain, as has been shown in a mouse model[1]. Mice fed soybean oil had more oxylipins, their fatty liver formed more quickly and their metabolism slowed[1][2]. In addition to obesity, excessive consumption of soybean oil can also negatively affect the gut microbiome, weaken the intestinal wall, and increase the risk of inflammatory diseases such as ulcerative colitis, as well as psychological problems such as anxiety and depression, according to the study[2]. The soybean oil used in the experiment contained approximately 19% linoleic acid, whereas the American Heart Association's recommendation is 5 to 10% of calories per day from omega-6 fatty acids, which linoleic acid belongs to[2]. Thus, research shows that the problem is not with the oil itself, but with the metabolites it produces in the body, which can have negative health consequences[1][2].