Abstract: A composition of exogenous ketones is provided which comprises one or more exogenous ketone bodies as well as one or more carbohydrates. More particularly, the one or more ketone bodies comprises beta-hydroxybutyrate, which provides a fuel source, and the one or more carbohydrates comprises resistant starch, which provides additional energy while preserving glycogen reserves and without causing insulin generation. In other embodiments, the carbohydrates comprise glucose, fructose, or other regular carbohydrates. The ketone bodies may also comprise acetoacetate and/or acetone. Unlike many conventional products, which spike blood sugar and result in an insulin surge, thereby blocking fat metabolism until the insulin and sugar is depleted, the inventive composition increases energy, improves insulin sensitivity, and enhances physical endurance during increased physical activity.