Rewards

In humans, it is argued that visual hunger – the desire to look at food – could have evolved because seeing food was generally a precursor to consuming food[1]. Long before the ascendance of culinary exhibitionism and food porn, the reward our brains would associate with the sight of food was the likelihood of a meal and survival, which in turn would trigger physiological responses to prepare to receive the imminent food intake.

Canine dopamine in action

Your dog’s anticipatory excitement as you prepare a meal, the circling, the drooling, the general canine shenanigans, are a similar activation of their systemic chain reaction. After enough good food memories, it is a conditioned (Pavlovian) reflex[2] that starts the ball rolling along the mesolimbic pathway – the brain’s reward route. Focus is about cognitive attention; the reward centre is about reinforcement and memory.

This is dopamine for dogs: the higher the reward, the greater the dopamine response[3]. Your dog’s love of a strong broth, for example, is no accident: the fat floating in that broth speaks straight to the brain’s reward circuitry.

The connection between dietary fats in a broth and the brain’s reward system is a sophisticated feedback loop. One of the brain’s key roles is to facilitate foraging and feeding, and its proximity to the mouth (and the canine nose) is presumably a design of nature. Or as British scientist J.Z. Young put it: “The fact that the brain and the mouth are both at the same end of the body may not be as trivial as it seems.”

Marking the memory

The reward experience unfolds as dogs enjoy their food, from the initial aroma to the end of the meal. The same reward pathway ensures that the act of eating is a highly reinforced psychological event that makes the brain want to return the next time for something equally pleasurable. This marking of high priority events is known as incentive salience.

“No animal can live without food. Let us then pursue the corollary of this: Namely, food is about the most important influence in determining the organization of the brain and the behaviour that the brain organization dictates.”[4]

The dopamine journey

To see how the reward system works, we must look at the physical layout inside the canine brain. The mesolimbic pathway is a biological distribution network which, once triggered, allows the spread of dopamine from the midbrain to other areas of the brain. Contrary to popular belief, dopamine is more about pursuit and wanting than the actual pleasure.

The Ventral Tegmental Area (VTA)

The VTA is where the dopamine journey starts. The second your dog’s nose catches the aroma of food, long before that first mouthful, the VTA initiates the spread of dopamine to other areas.

The Nucleus Accumbens

When dopamine floods this area, which controls motor functions and is central to reward processing, it generates a sense of anticipation and motivation. Micro-anticipation creates the drive to continue the eating rhythm, keeping the dog engaged and looking forward to the following mouthful – even after the initial novelty of the aroma has peaked.

Amygdala and Hippocampus

This is where the payoff is archived. The amygdala attaches an emotional value to the food profile, while the hippocampus forms memories.

Essentially, when the dopamine has travelled along these pathways and the memory is created, the dog will remember something worthy of pursuit or repetition. And a smart dog will also learn behaviour based on those signals.

Fats: rulers of  the reward pathway

Fat is a powerful motivator for food-seeking behaviour[5]. Why? Because it is uniquely potent. The real magic lies in how fat communicates, using three distinct channels simultaneously:

Olfactory bulb (scent)

Long before the food touches the tongue, airborne fat molecules drift into the nasal cavity, lighting up the olfactory system. This initial chemical signal alerts the VTA to start pumping out dopamine in anticipation.

Trigeminal nerve (texture and mouthfeel)

When the dog takes that first mouthful, the physical structure of fat and its coating texture mechanically stimulates the trigeminal nerve in the mouth, sending a sensory message directly to the brain about the luxury and physical quality of the food.

Vagus nerve (caloric sensing)

As the fat reaches the gut, specialised receptors detect its extreme nutrient density and bioavailability. The vagus nerve acts like a direct telephone wire from the digestive tract back up to the brain stem, confirming the arrival of high-value, calorie-dense fuel.

This multi-channel signalling is a deep-seated survival mechanism: the brain is hardwired to reward the intake of energy-dense fats because they deliver more than twice the energy of protein or carbs. And energy means survival.

Because lipids ignite these physiological and chemical channels simultaneously[6], the release of neurochemicals appears significantly higher than it would be for other nutrients. There is even a distinct difference in extracellular neurochemical release when fats are present, including a rise in beta-endorphins [7] that provide an instant sense of wellbeing and regulate emotion.

Last but not least, since the brain itself is around 60 percent fat, the reward centre is highly sensitive not just to the immediate payoff of triglycerides, but to the presence of essential fatty acids that support neuronal membrane fluidity – i.e. brain function.

Closing the Loop: The Gut-Brain Axis

A constant, two-way conversation takes place in the pathway between brain and digestive system. When high-value fats enter the gastrointestinal tract, the gut actively signals to the brain to reinforce the reward loop. This post-ingestive feedback is the final biological stamp of approval, confirming to the brain that the anticipation was justified, reinforcing the memory and the entire neural loop.

The takeaway

In canine behavioural science, many dogs are recognised as naturally neophilic. That means they possess an innate preference for novel scents, textures and flavours. The payoff isn’t just one feeling; it’s a layered chemical event that many of us can’t even begin to appreciate, involving dopamine (motivation or wanting); opioids like endorphins (liking or hedonic pleasure) and endocannabinoids (flavour enhancers).

When a dog is confined to a single, unvarying food profile day after day, this highly sensitive sensory apparatus is effectively under-utilised. Because the brain is wired to process and reward new environmental inputs, a more monotonous meal profile removes a source of daily mental stimulation.

Food variety, on the other hand, provides essential sensory enrichment. Each shift in ingredients introduces fresh volatile compounds to the olfactory bulb, new physical structures to the trigeminal nerve and varying macronutrient profiles to the vagus nerve.

Ensuring that mealtimes – and treats – remain a pathway-rewarding event.

*****

References:

[1] Spence C, Okajima K, Cheok AD, Petit O, Michel C. Eating with our eyes: From visual hunger to digital satiation. Brain Cogn. 2016 Dec;110:53-63. doi: 10.1016/j.bandc.2015.08.006. Epub 2015 Oct 1. PMID: 26432045.
[2] Pavlov PI. Conditioned Reflexes. London, UK: Oxford University Press: 1927
[3] Schultz W. Dopamine reward prediction error coding. Dialogues Clin Neurosci. 2016 Mar;18(1):23-32. doi: 10.31887/DCNS.2016.18.1/wschultz. PMID: 27069377; PMCID: PMC4826767.
[4] Young, J. Z. (1968, December). Influence of the mouth on the evolution of the brain. In Biology of the mouth: A symposium presented at the Washington meeting of the American Association for the Advancement of Science, 29–30 December 1966 (pp. 21-35). Washington, DC: American Association for the Advancement of Science.
[5] Wallace CW, Fordahl SC. Obesity and dietary fat influence dopamine neurotransmission: exploring the convergence of metabolic state, physiological stress, and inflammation on dopaminergic control of food intake. Nutr Res Rev. 2022 Dec;35(2):236-251. doi: 10.1017/S0954422421000196. Epub 2021 Jun 28. PMID: 34184629; PMCID: PMC9351269.
[6] Young, J. Z. (1968, December). Influence of the mouth on the evolution of the brain. In Biology of the mouth: A symposium presented at the Washington meeting of the American Association for the Advancement of Science, 29–30 December 1966 (pp. 21-35). Washington, DC: American Association for the Advancement of Science.
[7] Dittmann MT, et al. Low resting metabolic rate and increased hunger due to β-MSH and β-endorphin deletion in a canine model. Sci Adv. 2024 Mar 8;10(10):eadj3823.

Important Considerations:

  • Always consult your veterinarian before making any significant dietary changes, particularly where there are pre-existing health conditions or dietary restrictions.
  • If you are feeding commercial food, check the label for ingredients before giving more. Excessive intake of any foods can have adverse effects.
  • Ensure (where possible) that you use high-quality, organic products specifically formulated for pets (or better still, human grade ingredients) to avoid any potential adverse effects.
  • Introduce new foods gradually to avoid adverse effects such as gastrointestinal upset or diarrhoea.
  • I provide nutritional information purely as a helpful guide. Nutritional information on ingredients is obtained from the US Department of Agriculture’s FoodData Central site (https://fdc.nal.usda.gov/index.html) and any nutritional information provided in recipes is based on an online calculator: calories and other information will vary based on brands, ingredients and other factors.
  • Check nutrient levels and recommendations for your dog’s weight, age and activity. For example this nutritional guideline produced by FEDIAF.
  • I am not a professional canine nutritionist but supporting research is cited.
  • The recipes shared were created by me and tested in my kitchen – and tasted and approved by our doggy friends!

This post has also been published on Substack.