A lot of research on these topics assumes the existence of metabolic syndrome / syndrome x, which is a hypothetical syndrome that is the supposed to be the comm

A lot of research on these topics assumes the existence of metabolic syndrome / syndrome x, which is a hypothetical syndrome that is the supposed to be the common cause of obesity, diabetes, etc. Metabolic syndrome used to be very mainstream but I'm not sure it's taken quite as seriously in the scientific community recently. However, if you do assume the existence of metabolic syndrome, you can pretty much justify a link between anything that could potentially be its cause and obesity. For example, if seed oils cause some sort of metabolic dysfunction resulting in metabolic syndrome, then that would then result in obesity. Obviously, if you assume that obesity is just caused by excess consumption of calories, and that obesity is then the cause of diabetes, and that there is no separate metabolic syndrome it becomes harder to justify this kind of theory. That link doesn't explicitly use the terms "metabolic syndrome" or "syndrome x" but it seems like it is probably implicitly assuming its existence.