Intermittent fasting (IF) and time-restricted feeding (TRF) are popular dietary regimens because of their effects on weight loss and metabolic health. Many people also partake in IF/TRF to promote healthy aging and a longer life, though these benefits are more speculative. While calorie restriction and some types of fasting have been shown to extend lifespan in animals, no such data exist in humans.
If these interventions do in fact increase lifespan, that’s great. But who wants to live a longer life if they can’t also share these extra years with “man’s best friend”?
Dr. Matt Kaeberlein and colleagues seem to share this sentiment. They’re part of a group of researchers leading what is known as the Dog Aging Project (DAP), the goal of which is “to understand how genes, lifestyle, and environment influence aging…and use that information to help pets and people increase healthspan, the period of life spent free from disease.”
In studying the effects of lifestyle and environmental factors on healthspan and lifespan in dogs, the DAP can not only improve companion pets’ quantity and quality of life, but translate these findings to humans, who share many of the same diseases and age-related pathologies with dogs.
The DAP research group recently published a preprint article (meaning it is not peer reviewed) that provides some preliminary data on how meal frequency may affect the health, cognitive function, and disease status of dogs.
Dog owners participating in the project were told to report the frequency at which their dog was fed — either once per day or more than once per day (i.e. “twice”, “three or more”, or “free fed”). Participating owners also filled out two questionnaires: one to assess health status (the Health and Life Experience Survey or HLES) and another to assess cognitive function (the Canine Social and Learned Behavior Survey or CSLB).
The reported data were then used to analyze the relationships between feeding frequency and health/cognitive function outcomes after correcting for a variety of factors including sex, age, breed, body size, omega-3 supplementation (which could affect health outcomes), physical activity level, and history of training.
Dogs who were fed once per day scored, on average, 0.62 points lower on the cognitive function survey (with lower scores being better) than dogs fed multiple times per day. To put this in perspective, 0.62 points is the difference in scores observed between a 7 and 11 year old dog (i.e. ~4 years of aging).
Regarding health outcomes, dogs fed once per day had significantly lower incidences of gastrointestinal conditions, dental/oral conditions, orthopedic conditions, liver/pancreas conditions, and kidney/urinary conditions. While not significant, there was also some evidence that once per day feeding reduced the odds of cardiac, skin, cancer, and neurological conditions.
These are first-of-a-kind data that provide some very nice hypothesis-generating information on how meal frequency may impact the health and lifespan of dogs. While aging wasn’t an outcome of this study (it’s only been going on for around 1 year), several age-related diseases and correlates of aging (cognitive function) were assessed which at least provide some insight into these dogs’ healthspan and quality of life. As the DAP continues to accrue longitudinal data, we will eventually be able to see how interventions like eating one meal a day (OMAD) impact the aging trajectories of participating dogs.
As the authors point out, these data can’t be used to imply causation. For one, all of the outcomes including meal frequency and health-related data were self-reported by the dog owners and therefore, are subject to potential misreporting, bias, and other confounding. Furthermore, it’s almost impossible to ensure that everyone’s perception of “meal frequency” used in the study is the same. While this study excels in generalizability/practicality, it lacks the strictness of a well-controlled laboratory study.
Should you switch your pup to a once-per day feeding regimen as a result of these findings? Perhaps not. However, it seems that the current recommendation to feed dogs twice per day is somewhat arbitrary and, just like the standard 3 meals per day that humans are told to consume, probably lacks a foundation of evidence to support it. It may, in fact, be leading to ill health (if it results in overconsumption).
I actually posted a tweet several weeks ago where I asked my followers whether or not they fasted their dogs. I got some interesting responses and the general feeling that there are a good amount of pet owners whose companions eat just once per day (as do their owners).
I guess just like with humans, many different eating regimens can work for dogs. But if a certain meal schedule (i.e. once-per day feeding) could enhance my dog’s healthspan and lifespan, I’m willing to give it a try. We just may need a bit more data before making a definitive conclusion.
I’ve actually enrolled our dog Bannister in the Dog Aging Project and occasionally fill out surveys on his health and other information. It’s quite fun and a small way to contribute to aging science. Who knows, we may actually get some actionable data in the future that we can use to add a few years to his life.
If you’d like to participate in the project, you can find more information here. They’re always recruiting.
Thanks for reading. See you next Friday.
Once-daily feeding is associated with better health in companion dogs: Results from the Dog Aging Project. Emily E. Bray, Zihan Zheng, M. Katherine Tolbert, Brianah M. McCoy, Dog Aging Project Consortium, Matt Kaeberlein, Kathleen F. Kerr. bioRxiv 2021.11.08.467616; doi: https://doi.org/10.1101/2021.11.08.467616