Healthy vs Harmful Foods for Dogs

Feb 18
4 min read

When deciding what to feed your dog, it helps to step back from trends and marketing and look at biology. Dogs are classified as facultative carnivores. This means they are designed to thrive primarily on animal tissue, but they can digest and utilise certain plant foods. Their anatomy, digestive chemistry, and metabolic pathways still clearly reflect a carnivorous foundation. Understanding that foundation helps us distinguish between foods that support health, foods that are simply less optimal, and foods that are genuinely harmful.

The Biological Blueprint of a Dog

Dogs have:

Sharp carnassial teeth for tearing flesh
No salivary amylase
A short digestive tract
A highly acidic stomach (pH around 1–2 when digesting protein)

That strong stomach acid is designed to:

Break down muscle and connective tissue
Kill pathogenic bacteria
Release minerals from bone and meat

Metabolically, dogs are also adapted to use fat and protein as primary energy sources. They can create glucose from protein through a process called gluconeogenesis, meaning they do not have a strict dietary requirement for carbohydrates.

This biological framework explains why certain foods are foundational, others are supportive, and some are inappropriate.

SAY YES TO: Foods That Support Canine Physiology

Animal Proteins: The Foundation

Animal protein should form the core of a dog’s diet. Why? Dogs require:

10 essential amino acids from food
Adequate taurine (important for heart health)
Highly bioavailable iron and zinc
B vitamins for energy metabolism. Whole animal proteins provide complete amino acid profiles in forms that are easily absorbed.

Beneficial options include: Beef, lamb, pork, goat, veal, rabbit, venison, turkey, chicken (and eggs), duck (and eggs), quail (and eggs), kangaroo, ostrich, wild boar, pheasant, partridge, hare, horse, zebra, and camel.

Fish such as: Salmon, mackerel, sardines, sprats, herring, trout, Atlantic cod, Atlantic hake, mullet, and lemon sole provide long-chain omega-3 fatty acids (EPA and DHA), which help:

Modulate inflammatory pathways
Support joint integrity
Promote skin and coat health
Aid neurological function

Fermented Dairy (if tolerated) such as: Kefir, cottage cheese, and goat’s cheese with live cultures can provide probiotics and additional protein.

In summary: High-quality, varied animal protein improves nutrient density and biological appropriateness.

Fruits & Vegetables: Strategic Additions

Dogs do not require carbohydrates in the same way humans do. However, certain plant foods can offer functional benefits when used appropriately. They provide:

Soluble and insoluble fibre
Polyphenols and flavonoids
Antioxidants
Carotenoids
Vitamin C

Examples include: Apples (no pips), blueberries, raspberries, strawberries, cranberries, kiwi, mango, pineapple, banana, watermelon, broccoli, cauliflower, kale, cabbage, carrots, celery, courgette, butternut squash, pumpkin, sweet potato, green beans, asparagus, parsnips, bell peppers, Brussels sprouts, mushrooms, coconut (flesh/milk/oil), avocado (flesh only), olives.

Potential benefits of plant matter:

Fibre helps regulate bowel movements and feeds beneficial gut bacteria.
Antioxidants help neutralize oxidative stress.
Certain phytonutrients may support immune modulation.

However, plant matter should complement protein, not replace it. When starch-heavy ingredients dominate a diet, the macronutrient balance shifts away from what canine metabolism is optimized to handle.

Herbs, Seeds & Functional Additions

Some herbs contain bioactive compounds studied for their physiological effects.

For example:

Turmeric contains curcuminoids that influence inflammatory pathways.
Ginger may support digestion and gastric motility.
Chamomile contains apigenin, linked to calming properties.
Dandelion leaves may support liver function and bile flow.
Nettle provides trace minerals and may modulate inflammation.

Seeds such as pumpkin, sesame, sunflower, hemp, and chia provide fibre, minerals, and essential fatty acids.

Nuts like almonds, hazelnuts, walnuts, and Brazil nuts should be fed sparingly and ideally ground for digestibility. These are supportive additions, not dietary staples.

SAY NO TO: Toxic Foods

Some foods are dangerous because dogs lack the metabolic pathways to process certain compounds safely.

Strictly avoid:

Alcohol
Grapes, raisins, currants, sultanas
Chocolate
Xylitol and artificial sweeteners
Onions, leeks, chives
Macadamia nuts
Black walnuts
Blue cheese
Mould of any kind
Broad beans (fava beans)

Why they’re harmful:

Grapes/raisins: Linked to acute kidney failure, even in small amounts.
Chocolate: Contains theobromine, which dogs metabolize very slowly, affecting the heart and nervous system.
Xylitol: Triggers a rapid insulin spike, causing severe hypoglycaemia and potential liver failure.
Alliums (onions, leeks, chives): Can damage red blood cells, leading to anaemia.
Mould: Risk of mycotoxin poisoning.

These are not moderation foods; they are zero-tolerance foods.

Foods Best Avoided:

Rice (all types), maize (corn), wheat, bran, barley, bulgur, oats (gluten free preferred if used), peas, split peas, chickpeas, lentils, soybeans, kidney beans, butter beans, white potatoes, and red potatoes.

Why they should be avoided:

They are carbohydrate-dense
They can raise post-meal glucose and insulin levels
They often replace higher-quality protein in processed diets
Some legumes contain anti-nutrients like lectins and phytates, which may reduce mineral absorption

Dogs can digest starch, especially when it's cooked. However, just because starch is digestible doesn't mean it's ideal, especially when it makes up a large portion of their calorie intake.

Inflammation & Long-Term Health

Chronic low-grade inflammation is linked to:

Joint degeneration
Skin disease
Gut imbalance
Metabolic dysfunction

Diets high in ultra-processed carbohydrates and low-quality fats are likely to contribute to inflammatory load.

In contrast, diets centred around fresh animal proteins, natural fats, oily fish and whole-food antioxidants tend to support healthier inflammatory balance and metabolic stability.

The Bottom Line

A biologically aligned canine diet:

✔ Prioritises high-quality animal protein

✔ Uses natural fat as a primary energy source

✔ Includes plant foods strategically for fibre and micronutrients

✔ Avoids known toxins completely

✔ Minimises highly processed starch fillers

Every dog has its own biological quirks, which means their response to different foods can vary widely. Factors like genetics, age, gut microbiome diversity, previous diet, and overall health all influence how well a dog can digest and utilise new ingredients. Even foods that are generally safe and beneficial may cause mild digestive upset if introduced too quickly, simply because the gastrointestinal system needs time to adapt. That’s why gradual introduction is so important. When you add a new food slowly, you allow the digestive enzymes, gut bacteria, and GI motility to adjust at a comfortable pace. This approach reduces the risk of loose stools, gas, or discomfort, and it also helps you clearly identify whether the food is truly well tolerated.