As a veterinary nutritionist, I must first focus on the differences in nutrition and feeding behaviors in dogs. As humans, we hopefully eat a varied diet which may help to meet our nutritional requirements. (Note, I am not a human nutritionist.) That said, most of us do not understand or calculate our total nutritional needs nor do we measure each nutrient in our meals to ensure we are getting enough, or too much of, each nutrient.

My guess is that this likely leads to subclinical or clinical deficiencies in nutrients we are typically blissfully unaware of until there is an issue. What we eat is often dictated by availability, cost, and culture. I often think we do better with nutrition for our pets. Over the years we have studied canine nutrient requirements and have identified essential nutrients that when fed at specific amounts prevent deficiencies over time. We have also identified functional ingredients that further help to improve health when given at specific amounts.

We utilize this information when formulating complete and balanced dog foods. When feeding dogs human table foods and creating homemade diets which do not take these requirements into consideration, we can see many nutrient deficiencies.1,2,3,4 The most regularly encountered in the literature are zinc, choline, copper, EPA + DHA, calcium, iron, thiamin, riboflavin, cobalamin, vitamin D, and vitamin E.1,5
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Based on experience another common nutrient deficiency when dogs are fed homemade poultry-free diets is linoleic acid. In addition, since it is not commonplace for most owners to calculate the energy content of the diet they are feeding, dogs will often be underfed if they are large dogs and over-fed if they are small dogs resulting in weight loss or gain, respectively.

Humans and dogs have significantly different nutrient requirements. Dogs have a higher protein requirement, and they cannot produce vitamin D from the sun. For humans, vitamin D is only conditionally essential since it can be synthesized with ultraviolet B radiation of the skin from 7-dehydrocholesterol. Therefore, supplementation is only needed when exposed to ultraviolet light is limited.  However, dogs (and cats) have very little 7-dehydrocholesterol in their skin and so they can't produce vitamin D in this manner, and it must be in the diet. Unlike humans, dogs can produce vitamin C during the normal metabolism of glucose and thus do not have a vitamin C requirement.

Dogs also have unique feeding behaviors as anyone who has watched them gobble up cat litter-covered poop pops from the box can attest. At this point in their domestication dogs are dependent on humans for food. As for their natural feeding behaviors, we can look to feral populations and laboratory environments to gain information. Wild dogs hunt in packs and typically hunt medium-sized to large prey including deer and caribou. A dog can readily consume their entire daily caloric needs in just a few minutes in a single meal.  

Conversely, dogs offered free access to food in a laboratory setting will eat 4 to 8, or frequent smaller meals throughout the daylight hours with some breeds also eating during the night as well.6 So although adult dogs often do well with multiple small meals throughout the day they can also tolerate twice-daily feedings. Our dogs seem to enjoy certain foods, treats, and novelties and these offer a way to stimulate them in what could otherwise be a monotonous environment. Yet, we would not expect a dog to smell and take the time to savor its meal the way we might if we went home for Nonna's cooking.

That means that using food and food dispensing toys to encourage environmental and mental stimulation and hand-feeding while training is very important. However, please keep in mind that many dogs do well, or even better, with a consistent well-balanced diet and do not necessarily need a rotation of flavors or types of food. 

There is one area where dogs and humans are similar. Each dog, like each person, is an individual. While one dog may benefit from a high-fat, high-protein diet, fed once daily to accommodate for its athletic activities, another dog may experience severe GI upset when fed in that manner. It is common for nutritional fads for humans to make their way into marketing for new dog foods which can pose nutrition and health risks.

One concerning trend is to try to incorporate new and novel ingredients that are not well understood into the diet and supplements. While benefits of these ingredients are certainly possible so is the risk of toxicities and nutrient interactions. Companies should exercise caution when investigating new ingredients and owners should be careful about using novel or multiple supplements without discussing it with their veterinarian.

It is not just nutrition and metabolism that makes dogs different from humans, but fundamentally who they are as a species. Dogs are meant to run and sniff. They need their human to fulfill their part of the human-animal bond by providing an enriching life alongside rules and boundaries that keep dogs safe and happy.

Their individual breeds may also be genetically wired to herd, hunt, protect, or be a companion. When we try to make them into small humans by carrying them when they can walk and not giving them opportunities to explore and be comfortable in their environment with and without us, we cut off a portion of who they really are. When we do not help them understand appropriate or inappropriate behavior through consistency and training and providing appropriate outlets for behaviors that can be dangerous in certation situations, we see an increase in anxiety and destructive behaviors.

Over the years I have had more and more dog owners requesting medication to modify anxiety and undesirable behaviors when it would be more appropriately managed with behavioral modification and preventative measures such as training and exercise. While there are times when medications can reduce stress enough to help make behavioral modification more successful, it is not meant to be the quick-fix people desire. The best measure to take against having your beloved pup live its healthiest life mentally and physically is to remember they are in fact dogs, with different nutritional and behavioral needs than humans.

by Renee Streeter, DVM, DAVCIM - BSM Partners