Fussy Eating in Dogs – The Alternative Dog

I wouldn’t necessarily define George my German Shepherd as a fussy eater but when he was our only dog, many moons ago, he would be super-excited for his bowl of food (dancing and spinning around the kitchen) but when I put it down, he would take a sniff, look disappointed and walk away. Obviously, I was deeply concerned by this. If he didn’t eat, he wouldn’t thrive. To cut a long story short, it turned out that he just didn’t like dry food. Once he was swapped to a raw food diet, he ate every single morsel and licked the bowl clean.

For many fussy eaters, the switch to a raw diet is all it takes. But there are dogs who continue to be fussy no matter what food they are offered. What is going on? In this article, I’ll explore what fussy eating is, feeding behaviour in dogs, the reward system, the influence of hormones and neurotransmitters, stress and of course some top tips to support that fussy eater.

What is Fussy Eating?

Fussy eating is, in essence, an eating disorder. There are several possible causes from behavioural to biochemical. To understand the condition, we need to begin by considering the function of food and why our dogs eat.

The function of eating

Hunger and appetite are two quite separate things. Food is what your dog needs for energy and for health. As the body carries out its tasks, it uses fuel and compounds. As reserves run low, signals bounce around the body. This is what we know as hunger, the physical need to eat. It is what drives feeding behaviour.

Appetite on the other hand is the desire to eat.

Hunger and appetite can be at odds. You may want to eat, but not need to, and you may need to eat, but not want to (in times of stress for example). This exact mechanism also applies to our dogs.

The brain and food

Appetite and hunger are largely controlled by the brain and several hormones. So, when we are looking at feeding behaviour, it pays to think about what may be going on in the brain.

In the brain sits the hypothalamus. Through its connection to the pituitary gland, it modulates the endocrine system (consisting of organs, glands and hormones). The hypothalamus is involved in a range of daily activities including temperature regulation, but it also plays a role in eating behaviour. We know this because many studies have highlighted that when there are lesions to small areas of it can result in overeating and undereating behaviour. The lateral hypothalamus is defined as the feeding centre and the ventromedial hypothalamus is defined as the satiety centre.

This is largely an oversimplification, but it certainly demonstrates the role. The hypothalamus receives information from the digestive system. This includes when the stomach extends to receive food, but also the chemical nature of ingested food and the metabolic activity of the liver. The hypothalamus uses all this information to maintain energy balance.

Food as a reward

Food should ultimately be a rewarding object that induces pleasant emotions, because why else would you (or your dog) continue to do it? Studies have demonstrated that when the reward value of food decreases, so too does eating motivation. Sadly, these studies often include the injection of lithium after eating, of which causes discomfort. But it does raise an interesting point in terms of the fussy eater in your life. I’ll come back to this concept a little later.

Food reward is elicited by several events that occur before food even passes through the oesophagus, namely the appearance and shape of the food, the taste and smell and then the pleasure of swallowing the food. We know this because in tube-feeding studies, reward sensations are reduced. In short, when subjects were no longer allowed to taste or chew food, they didn’t want to eat it. On the other hand, in sham studies, when animals are denied nutrition because everything swallowed leaks out of a tube connected to the oesophagus, the animals eat and swallow more than usual but remain unsatiated in terms of reward. This tells us just how complex eating behaviour is. It also provides food for thought for the gluttonous dog (on the other side of the scale).

Hormones and Eating Behaviour

Hormones are probably the most talked about in terms of eating behaviour. You’ve likely come across leptin and ghrelin. Leptin is produced in adipose cells, or fat cells. So, the more fat cells there are in the body, the more leptin. In short, the more fat available in reserves, the less your dog needs to eat. If your dog has no fat cells, they need to conserve energy until they next find food. Leptin crosses the blood-brain barrier, and there are high numbers of leptin receptors found in the hypothalamus, brain stem and other regions of the brain. High leptin levels inhibit food intake by suppressing a range messenger molecules involved in eating behaviour.

The other hormone ghrelin is predominantly secreted in the stomach, and it too modulates cells found in the hypothalamus. Ghrelin is seen to have a large influence on the release of the neurotransmitter dopamine. As dopamine is involved in reward and motivation (amongst other behaviour), ghrelin is thought to target the motivational functions geared to gaining food and to select those which are more rewarding (high calorie). As dopamine also plays a role in aggression, it could also explain why we may get “hangry.”

Eating behaviour and neurotransmitters

Neurotransmitters are chemical messengers, and they play several roles in the body, including influencing eating behaviour.

In eating disorders, dopamine is one of the neurotransmitters that gets a lot of attention. In times of reduced food intake (fussy eating), dopamine neurons are activated, in the short-term rewarding the lack of food. It is considered that it is a physiological response to increase motivation to forage for food. However, there are also other mechanisms in which the dopaminergic system comes into play for the fussy eater. A central feature of the dopamine neuron response is that it’s triggered by un-expectancy.

After receiving an unexpected reward like food (or how many likes our recent post has got on social media) a dopamine surge is elicited. The dopamine signal is triggered by the conditioned stimulus in predicting the reward. Over time, the mealtime reward isn’t the same – it becomes predictable. In addition, us and our dogs can simply not find the reward, all that rewarding. What this means, is that your dog may do the song and dance ready for their bowl of food, but then walk away as soon as it is placed in front of them (like George). The reward they predicted (tasty food), isn’t what was received.

The other neurotransmitter that gets attention in eating behaviour is serotonin or 5-HT. 5-HT has a well confirmed role in the regulation of eating behaviour. Manipulations to increase it have led to reduced eating behaviour and those to reduce it precipitate binge eating behaviour. This suggests another multifactorial mechanism that indirectly effects eating behaviour. Serotonin is a key player in feelings of nausea – so higher levels could be produced in response to something not sitting quite right in the digestive system. Poor serotonin metabolism can also contribute to high levels. Whenever something is produced in the body, it needs to be used and then broken down. Serotonin is metabolised largely by monoamine oxidase (MAO) so it stands to reason that MAO inhibitors can contribute to high levels in the body. Sadly, certain insecticides found on flea and tick collars contain MAO inhibitors. This suggests that your dog may experience higher serotonin levels than expected, contributing to feelings of nausea. There are also certain dietary supplements that can increase 5-HT including ginseng, turmeric, rhodiola rosea, l-theanine and St. John’s Wort.

So, in some cases, more is not always better and returning to basics for the fussy eater may be crucial. There is also a link between high serotonin levels, anxiety, and obsessive-compulsive type behaviours, suggesting that there is also a place for stress behaviour coinciding with fussy eating patterns. Let’s explore stress in a little more detail.

Stress and eating behaviour

Stress is a biological response to a perceived threat. It consists of two elements: the fight or flight response and the rest and digest response. During the fight or flight response, resources are directed to where they are needed and away from the digestive system. This is apparent for many of us pet owners. How many times, during stressful experiences, have you just not wanted to eat? Corticotropin-releasing hormone is released as part of the stress response, and it is conclusively linked with decreased eating patterns. Not surprisingly, this can apply to our dogs too. If they are faced with chronic stressors like health issues or environmental challenges including people and other pets, then their resources will largely be diverted away from their digestive system. But its pertinent to note there is also evidence which links stress to increased eating patterns. This is largely due to the resources utilised in the stress response and the body seeking energy-dense foods. Repeated and uncontrollable stress dysregulates the hypothalamic-pituitary adrenal axis; this in turn activates the dopaminergic system of which I mentioned earlier. This drives us and our dogs to forage for more food! There is seemingly a fine line between stress driving under or overeating; its therefore important to consider your dog’s eating behaviour alongside their lifestyle, other behaviours, health challenges and more!

Fussy eating is a complex subject

As you can see, fussy eating is complex. So, how do we support the dog who just isn’t that interested in their food?

First and foremost, your dog may just not like the food they are being offered. In terms of reward pathways, it’s just not lighting their fire. Furthermore, there could be some learned behaviour that is telling them to avoid the food on offer.

If they have felt unwell after eating it before, then they’d do well to avoid it in future. This doesn’t even have to be sinister in terms of a gastro bug, it could merely be a sensitivity. In addition, it could be due to lack of digestion from a poorly functioning liver or pancreas. Long term medication use could have resulted in limited stomach acid or there could be poor integrity in the gut that warrants some healing. There could be a range of underlying issues which just make mealtimes and the following digestion, particularly uncomfortable. This can also include dental issues. Whether current or past. Dogs are incredibly good at hiding their pain or discomfort, it wouldn’t have boded well in terms of evolution; a sign of weakness places them as an easy target for predators. So, it’s up to us to observe and notice patterns in their behaviour.

We must also consider stress. For both human and pet. If they are exposed to acute or chronic stress, it could remove their desire to eat. That said, as someone caring for a fussy eater, we too can become stressed and anxious that our dog isn’t getting the nutrients they need to thrive. Unfortunately for us, dogs have incredible olfactory capabilities, meaning they can smell our stress! They also have this capacity to mirror our emotions. And so, when they don’t eat, we get stressed, so they get stressed and may be even less likely to eat.

Top tips for managing a fussy eater

Eliminate any physical reasons why your dog may not be eating (blockages, dental issues etc).

Establish mealtimes – there’s no unexpected reward if a bowl of food is always available.

Offer fresh food with a range of tastes, aromas, and textures.

Variety is the spice of life – use novel proteins – what’s more unexpected than novelty? This can also be helpful if you are concerned your dog may have a sensitivity to certain foods.

Slightly heating the food alters its aroma and texture making it more enticing.

Offer food in bowls or plates, or even on wooden boards. Consider raising it off the ground.

Consider the material of the bowl/plate you offer. Some dogs prefer porcelain, some prefer glass. The aroma from plastic bowls, especially if they have been in the dishwasher can be off-putting. Remember a dog’s nose is around 40 times better at smelling things than us humans.

Avoid distractions. If there is always something more interesting going on and feeding time it can result in disinterest in the actual food. Offer mealtimes in quiet areas of the home and when it’s calm. Could the presence of another animal – maybe a cat – be causing the problem?