Understanding your pet’s diet

​​The origins of pets stretch back millions of years, yet their domestication is relatively recent in evolutionary terms.

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Evolution and Domestication

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Dogs

Did you know that whether your pooch is a 1 kg Chihuahua or a 120 kg St Bernard, they’re both descendants of the wolf? Dogs share ancestry with wolves, foxes, and other members of the Canidae family, which appeared about 40 million years ago. The Canis genus - including wolves, coyotes, and dogs - evolved roughly 3 to 5 million years ago.

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Domestication began around 20,000 to 40,000 years ago, when friendly wolves formed mutually beneficial relationships with humans, assisting in hunting and offering protection. Over time, adaptation to human life and diet shaped the modern dog’s physiology. Selective breeding intensified in the 19th century, shifting from working traits like herding and hunting to appearance and temperament - sometimes at the expense of health, leading to inherited disorders such as hip dysplasia and respiratory issues.

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Cats

Cats evolved from the Felidae family around 10 to 12 million years ago. The Felis lineage, including the African wildcat (Felis lybica), emerged 3 to 4 million years ago. Domestication occurred around 9,000 to 10,000 years ago in the Near East, where wildcats helped control rodents near grain stores.

Unlike dogs, cats domesticated themselves - those tolerant of human presence thrived near settlements. Selective breeding began in the late 19th century, focusing on coat color, body shape, and temperament rather than working ability.

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Understanding this evolutionary backdrop helps explain the nutritional needs of modern pets.

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Digestive Physiology and Dietary Adaptations

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Both dogs and cats are monogastric - they have a single-chambered stomach and a short digestive tract designed for rapid digestion. They are carnivorous by nature, adapted to diets rich in animal protein.

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• are obligate carnivores, requiring nutrients found only in animal tissue.

• are omnivorous carnivores, primarily meat-eaters but capable of digesting plant material - an adaptation from living alongside humans.

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Domestication, especially in recent decades, has significantly altered pet nutrition. The rise of commercial pet food since the 1950s introduced convenience and consistency, but also highly processed diets that differ greatly from ancestral feeding patterns.

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Nutrients and Digestion

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Pets rely on six essential nutrient groups: protein, fat, carbohydrates, minerals, vitamins, and water.

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• Carbohydrates (simple sugars and starches) are broken down into glucose, a fuel source. Excess carbs are stored as fat.

• Dogs’ stomachs are highly acidic - ideal for digesting raw meat and bone, but not starch. Undigested carbs can disrupt gut microbiota, leading to dysbiosis.

• Cats lack enzymes to digest starch efficiently and rely on moisture-rich food due to a weak thirst drive.

 

Feeding Behaviors in Nature

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Dogs

Wolves are intermittent feeders, consuming large meals when available. Dogs retain this trait - they can expand their stomach to hold up to 5% of their body weight. This explains their tendency to eat quickly and overeat if allowed.

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Cats

Cats evolved to hunt small prey frequently. Their digestive system is optimized for high-protein, high-fat diets with minimal carbs. Their natural feeding pattern involves multiple small meals throughout the day, not large portions. Unlike dogs, cats have a weak thirst drive and rely heavily on their food for hydration - their wild ancestors obtained most of their moisture from prey.

 

 

 

 

 

 

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The Modern Pet Diet

 

Nature offers few sources of starch, yet human diets rely heavily on carb-rich grains like wheat, corn/maize, and rice - which have influenced pet food formulations.

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• Commercial kibble often contains 30-60% carbohydrates, mostly from cheap fillers.

• Excess sugar and starch are linked to diabetes, obesity, IBD, and immune dysfunction.

• Protein quality matters more than quantity. Many pet foods use low-grade animal by-products such as feathers as protein sources.

• Low moisture content (5-10% vs. 70-80% in prey) is especially problematic for cats with their weak thirst drive, leading to dehydration and urinary issues.

 

Processing also affects nutritional value:

• Enzymes, vitamins, and minerals are destroyed above 49°C/120°F, yet processing temperatures often exceed 200°C/390°F.

• Heat can turn fats into toxins, weakening the body over time.

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Feeding for Health

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While most pet owners intend to nourish their companions with love, the pet food industry doesn’t always prioritise optimal health. Understanding what your pet’s digestive system has evolved to eat - and how domestication has changed those needs - is key to making informed feeding choices.

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Feeding closer to nature means prioritising high-quality animal protein, moderate fat, and avoiding processed carbohydrates. Look for transparency in ingredient sourcing, avoid unnecessary fillers, and ensure adequate hydration - especially for cats, whose natural prey-based diet is rich in moisture.

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Every pet is unique. Factors like age, breed, activity level, and health status influence their nutritional needs. Working with a qualified animal nutritionist can help you cut through conflicting information, assess your pet’s diet, and design a feeding plan that supports long-term vitality and well-being.

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By understanding how evolution has shaped your pet’s biology - and making choices that respect it - you can provide nutrition that truly honours their nature.