How Nutrition Affects Your Dog's Behaviour, Mood, and Energy Levels

Introduction

Behavioural issues are often approached through training alone, but diet plays a powerful — and often overlooked — role in how dogs feel and behave. The connection between nutrition and behaviour is complex, but understanding it can help owners support their dogs more effectively.

The Food–Behaviour Connection

The brain is an energy-hungry organ. Despite accounting for only about 2-3% of a dog's body weight, the brain uses approximately 20-25% of the body's total energy. This high energy demand means that what dogs eat directly impacts brain function and, consequently, behaviour.

Poor nutrition can contribute to hyperactivity, anxiety, poor focus, and irritability. Fluctuating blood sugar and low-quality ingredients can amplify these issues. When the brain doesn't receive consistent, high-quality fuel, it can't function optimally.

Energy Spikes and Crashes

Highly processed diets can cause rapid energy spikes followed by crashes. This may look like bursts of excitement, restlessness, or difficulty settling. Foods high in simple carbohydrates cause rapid blood sugar increases, followed by dramatic drops. This cycle creates unstable energy patterns.

Dogs experiencing blood sugar fluctuations may seem hyperactive shortly after eating, then become lethargic or irritable as blood sugar drops. This pattern can make training difficult and contribute to behavioural inconsistency.

Stable energy often comes from consistent, nutrient-dense food. Diets with appropriate protein levels, complex carbohydrates, and healthy fats provide steady glucose release, supporting more stable energy throughout the day.

Gut Health and the Nervous System

The connection between gut health and behaviour isn't just speculation—it's well-documented science. The gut-brain axis describes the bidirectional communication between the digestive system and the central nervous system.

A significant portion of neurotransmitters—chemical messengers that affect mood and behaviour—are produced in the gut. Serotonin, often called the "feel-good" neurotransmitter, is primarily produced in the intestines. When gut health suffers, neurotransmitter production can be affected.

Digestive imbalance can affect stress response, mood stability, and immune signalling. Dogs with poor gut health may show increased anxiety, decreased ability to handle stress, and behavioural changes that seem unrelated to training or environment.

Supporting digestion supports emotional regulation. Probiotics, prebiotics, and easily digestible proteins can help maintain healthy gut bacteria, which in turn supports neurotransmitter production and overall brain health.

Inflammatory Responses and Behaviour

Chronic inflammation, often triggered by poor diet or food sensitivities, can affect brain function. Inflammatory molecules can cross the blood-brain barrier and influence mood, cognition, and behaviour.

Dogs with food sensitivities may experience low-grade inflammation that contributes to irritability, restlessness, or difficulty concentrating. Addressing food sensitivities—often through elimination diets or limited-ingredient foods—can sometimes dramatically improve behaviour.

Nutrient Deficiencies and Behaviour

Specific nutrient deficiencies can directly impact behaviour:

B Vitamins

B vitamins play crucial roles in energy metabolism and neurotransmitter synthesis. Deficiencies can contribute to lethargy, irritability, or anxiety. Whole food sources of B vitamins—organ meats, eggs, certain vegetables—are generally more effective than synthetic supplements.

Omega-3 Fatty Acids

These essential fats support brain structure and function. Dogs deficient in omega-3s may show decreased cognitive function, mood issues, or difficulty learning. Fish oils and certain plant sources can help address these deficiencies.

Protein Quality

Inadequate or low-quality protein can affect neurotransmitter production. Amino acids from proteins are building blocks for neurotransmitters. Without sufficient high-quality protein, the brain can't produce these essential molecules effectively.

Antioxidants

Antioxidants protect brain cells from oxidative stress. Dogs lacking adequate antioxidants may show signs of premature cognitive decline or difficulty with complex tasks. Fresh fruits and vegetables can provide natural antioxidants.

Training Works Better When Nutrition Supports It

Dogs that feel physically well focus better, recover faster, and respond more consistently to training. When nutrition isn't optimal, training can be frustrating for both dog and owner. A dog struggling with energy crashes, digestive upset, or nutrient deficiencies simply can't perform at their best.

Training and diet are not separate systems — they work together. Good nutrition sets the foundation for effective training. A well-fed dog has the physical and mental resources to:

• Maintain focus during training sessions
• Process and retain information effectively
• Regulate emotions and respond appropriately to cues
• Have the energy to practice and improve skills
• Recover from training stress and maintain enthusiasm

Recognising Behaviour Related to Diet

Some behavioural signs that might indicate nutritional issues include:

• Hyperactivity or restlessness after eating
• Lethargy or "crashing" between meals
• Difficulty settling or relaxing
• Increased anxiety or reactivity
• Poor focus or attention span
• Irritability or mood swings
• Destructive behaviour that seems unrelated to boredom
• Changes in behaviour that correlate with feeding times

These signs don't always indicate nutritional problems—behaviour has many contributing factors. However, when behaviour changes correspond with dietary changes, or when training improvements plateau despite good training methods, nutrition may be a factor worth exploring.

Working with Professionals

If you suspect nutrition might be affecting your dog's behaviour, consider consulting with:

A veterinarian can rule out medical causes of behavioural changes and help identify potential nutritional issues. A veterinary nutritionist can evaluate your dog's diet and recommend specific changes. A certified dog behaviourist can help assess whether behaviour issues stem from nutrition, training, environment, or a combination.

Often, addressing behaviour requires a multi-faceted approach—training, environment management, and sometimes nutritional support work together.

Making Nutritional Changes to Support Behaviour

If you decide to make nutritional changes to support better behaviour:

Change gradually—sudden dietary shifts can cause digestive upset that worsens behaviour temporarily. Monitor closely—track both physical health (energy, stool quality, skin condition) and behavioural changes. Be patient—some behavioural improvements take weeks or months to appear. Keep training—nutritional support enhances training but doesn't replace it.

Final Thoughts

Behaviour is communication. Sometimes what looks like a training problem is a nutritional one. Supporting the body often supports the mind.

The relationship between nutrition and behaviour is complex and individual. What works for one dog may not work for another. The key is remaining observant, being willing to explore various factors, and understanding that optimal behaviour often requires supporting the whole dog—body and mind together.

By recognising that training and nutrition work in partnership, owners can create more effective approaches to supporting their dogs' wellbeing. A well-nourished dog is better equipped to learn, adapt, and thrive in their environment.