A common factor in calorie restriction, intermittent fasting, and time-restricted feeding is time spent in a state of hunger. More time spent hungry may be better, up to a point. The signaling associated with hunger upregulates cellular maintenance processes such as autophagy, known to improve health over the long term. While the biochemistry is under ever greater exploration, there is still a lot of work to be accomplished in order to map the dose-response curve for calorie intake versus time spent hungry, as well as how that dose-response curve may differ in different mammalian species. One might look at recent discussions regarding the structure of studies in mice to see that assessments are not as straightforward a matter as might be imagined: mice in studies of calorie restriction are fed once a day. How much of the resulting health benefits are due to this time-restricted feeding versus reduced overall calorie intake?
A variety of diets have been studied for possible anti-aging effects. In particular, studies of isocaloric time-restricted feeding in laboratory rodents have found evidence of beneficial health outcomes. Companion dogs represent a unique opportunity to study diet in a large mammal that shares human environments. The Dog Aging Project has been collecting data on thousands of companion dogs of all different ages, sizes, and breeds since 2019.
We leveraged this diverse cross-sectional dataset to investigate associations between feeding frequency and cognitive function (n = 10,474) as well as nine broad categories of health outcomes (n = 24,238). Controlling for sex, age, breed, and other potential confounders, we found that dogs fed once daily rather than more frequently had lower mean scores on a cognitive dysfunction scale, and lower odds of having gastrointestinal, dental, orthopedic, kidney/urinary, and liver/pancreas disorders. Therefore, our findings suggest that once-a-day feeding in dogs is associated with improved health across multiple body systems.