The present invention provides a method for increasing mobility or activity in an animal or treating or preventing frailty in an animal, comprising identifying an animal with decreased mobility or activity or having frailty and administering a composition comprising one or more medium chain triglycerides (MCTs) to the animal in a therapeutically amount effective for increasing mobility or activity in the animal or treating frailty in the animal. Additionally, a food composition can comprise about 15% to about 50% protein, about 5% to about 40% fat, about 5% to about 50% carbohydrate, and about 1% to about 40% of one or more medium chain triglycerides (MCTs); wherein the composition has a moisture content of about 5% to about 20% and the MCTs are present in a therapeutically amount effective for increasing mobility or activity in the animal or treating frailty in the animal.