This study was conducted to evaluate dietary trans-10, cis-12 conjugated linoleic acid (t10, c12-CLA), given the studies showing that supplemental doses has a negative impact on insulin resistance. To that end, we produced a 60% high fat diet composed of butter produced from milk collected from dairy cows suffering from subacute ruminal acidosis (SARA) – a condition that can sometimes result from the dairy industry production practice of feeding a high grain, low forage diet to milk-producing cows. This butter represents the most t10, c12-CLA-enriched source of naturally occurring t10, c12-CLA for humans. We compared the effects of the high t10, c12-CLA butter against a commercially available butter in a high fat diet-induced rodent model of insulin resistance. After 8 weeks, whole body glucose homeostasis was evaluated along with markers of inflammation, indicated by mitogen-activated protein kinase (MAPK) activation.