Older beagle dogs were placed into cognitively equal groups where a ‘treatment’ group ate a diet supplemented with 5.5% MCT for eight months. Subsequently, all dogs were assessed on four cognitive competencies. The treatment group showed significantly better performance over the control group in most test protocols, particularly on more difficult tasks, as well as significantly elevated levels of β-hydroxybutyrate, a ketone body. Conclusions from the study are that long-term supplementation with MCT can enhance cognition in aged dogs and increase circulating levels of ketones, by providing the brain with an alternative energy source.