Trans-palmitoleic acid (trans-C16:1) is a naturally occurring trans fatty acid present in small quantities in foods, most notably in dairy products. Observational evidence suggests a positive association between trans-C16:1 and insulin sensitivity, and negative association with risk of developing type 2 diabetes mellitus [1-3]. Cis-palmitoleic acid (cis-C16:1) is found naturally in foods and is particularly high in macadamia nuts and oil extracted from the sea buckthorn plant. Animal models suggest that this palmitoleic acid isomer also improves insulin sensitivity and reduces metabolic dysfunction.