Serum triglyceride levels are associated with metabolic disorders; however, it remains unclear whether the fatty acid (FA) composition of triglycerides is also changed. Although there were no differences in circulating triglyceride levels between normoglycaemic–normoinsulinaemic and hyperglycaemic–hyperinsulinaemic men, inspection of individual FA revealed that vaccenic acid was enriched with hyperglycaemia–hyperinsulinaemia. Moreover, vaccenic acid levels were positively correlated with insulin and HOMA-IR. This reinforces that examination of individual FA in the context of insulin resistance is warranted.