Why first meals matter: Raw nutrition and puppy and kitten gut health

What your new puppy or kitten eats in their first weeks and months of life has a profound, lasting effect on their gut microbiome, immune system, and long-term health.

Whether you've just welcomed a bouncing Labrador pup or a tiny tabby kitten, the same core principle applies: early nutrition isn't just feeding today's growth, you're also influencing their wellbeing throughout adulthood and into their senior years.

While you're watching them discover the world for the first time, a microscopic world is being built inside their gut. One that will shape how healthy they are for the rest of their life.

Their tiny microbiome's, the ecosystem of bacteria and microorganisms that live in the digestive tract, is developing and what you feed them in those first weeks and months matters far more than most people realise.

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The gut is where everything starts

A young pet's gut isn't just there to digest food. It's also the home of gut-associated lymphoid tissue which is essentially a training ground for the immune system. Around 70–80% of immune cells reside in or around the gut, and in early life, the bacteria your puppy or kitten encounters help determine those cells. They teach the immune system what's friend and what's foe.

Laying those foundations well means you're setting your puppy up for life with a well-regulated immune response.

Research Highlight

A study by the University of Helsinki followed thousands of Finnish dogs and found that puppies fed a non-processed, meat-based diet during the first six months of life were significantly less likely to develop chronic gut disease as adults. Those puppies fed an ultra-processed, carbohydrate-heavy diet faced a meaningfully elevated risk of conditions like inflammatory bowel disease. Raw bones and cartilage during puppyhood were highlighted as particularly protective. (Read More)

A critical window you can't get back

2-6 months

Microbiome development is the most critical during the early months of a puppy's life. During this time, the gut is especially receptive to the microbes and nutrients it encounters. A puppy raised on a diverse, minimally processed diet during this phase tends to develop a rich and diverse microbiome.

A study tracked dogs from two to fourteen months and confirmed just how rapidly the gut bacterial community changes in early puppyhood. The microbial landscape at two, three, and five months was dramatically different from what it looked like at eight months and beyond. Suggesting that dietary choices in those earliest months carry the most weight.

Kittens follow a similarly rapid and sensitive developmental timeline. One study tracked 30 kittens and found that structural and functional diversity of the gut microbiome increased significantly between 18 and 30 weeks.

Separate research confirmed that a kitten's diet at 8 weeks has a measurable effect on the species richness and diversity of the gut microbiome. Kittens fed a high-protein, low-carbohydrate diet showed greater microbial diversity.

This matters because kittens are obligate carnivores and their digestive biochemistry is designed around the nutrients found only in animal tissue. They cannot synthesise taurine or vitamin A from plant sources, and without adequate bioavailable protein, during early life stages kittens face the risk of developmental delays, weakened immune systems, and irreversible damage to vision and heart function.

Raw feeding and the puppy immune system

The immune system matures alongside the gut microbiome, learning from it. When the gut is made up by a diverse array of beneficial bacteria, the immune system develops the ability to distinguish between genuine threats and harmless substances like pollen or food proteins.

When the gut is disrupted, the immune system can become overactive or misdirected. This is part of the biological explanation for allergies, atopic dermatitis (skin conditions), and chronic inflammation.

A research group at the University of Helsinki has spent over a decade investigating this. Their data from thousands of dogs showed that puppies fed more raw, non-processed food had significantly lower odds of developing allergy, atopy, and chronic gut disorders in adulthood. Puppies fed kibble were found to be substantially more likely to show environmental allergy symptoms as adult dogs.

Research Highlight

A study extended these findings beyond gut health: the puppy's first solid diet and their diet from 2–6 months of age were both independently associated with a lower risk of chronic ear infections (otitis) in adult life when early meals were based on non-processed meat. The researchers concluded that early dietary programming shapes immune responses far beyond the digestive system itself. (Read More)

It starts even before the first mouthful

The microbiome story begins before puppies and kittens even enter the world. The mother's diet during pregnancy influences what bacteria and immune signals their offspring is exposed to in the womb and through her milk. A mother fed a nutrient-dense, raw diet during pregnancy and lactation is better positioned to pass protective microbial signals to her offspring. Studies have found that the maternal diet during pregnancy was associated with reduced risk of both gut disease and ear infections in offspring.

You can read more on feeding a raw diet throughout a bitch's pregnancy here.

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What the gut actually needs from food

A healthy young microbiome is built on:

Bioavailable protein from quality animal sources, which supports growth, neurological development, immune function, and energy.

Natural fats for brain and nervous system development and fat-soluble vitamin absorption.

Raw bone for minerals, texture, and dental health. A study in dogs found that those fed a non-processed meat-based diet during weaning, puppyhood, and adolescence were significantly less likely to develop dental calculus later in life.

Organ meat dense in micronutrients including taurine (critical for cats), iron, zinc, and B vitamins.

Vegetables and superfoods providing fibre and phytonutrients that beneficial bacteria need to thrive.

Research Highlight

A study of 4,771 dogs found that those fed a non-processed meat-based diet during weaning, puppyhood, and adolescence were significantly less likely to develop dental calculus later in life. Dental disease in dogs is closely linked to inflammation, and the effect was consistent across all three early life stages. (Read More)

Person in yellow shirt feeds a small brown dachshund puppy from a purple bowl in a kitchen.

Our Puppy Formula is suitable from six weeks of age and has been made with high quality, meat, bone and offal which has been finely ground to be a suitable size for puppies. Our puppy recipe also contains a carefully chosen blend of vegetables and natural superfoods to nourish the microbiome, support digestion, and lay the groundwork for a strong immune system.

For those just starting out, our Puppy Nuggets Starter Pack makes transitioning simple: pre-portioned, easy to defrost, and formulated to the same complete nutritional standard.

Our puppy feeding guide walks you through exactly how much to feed at each stage, from the first tentative mouthfulls to full raw meals in adolescence and adulthood.

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The long game

The science into raw feeding is still growing, but the direction is remarkably consistent for both species. Study after study from some of Europe's leading veterinary nutrition researchers points to the same conclusion: the meals puppies and kittens eat in their first few months of life are not just feeding today's growth but are actively influencing their future health.

A gut microbiome shaped by raw, varied, minimally processed food in early life is better prepared to regulate the immune system, resist infection, support healthy digestion, and guard against chronic disease.

Frequently Asked Questions

Does raw feeding improve puppy gut health?

Yes. Research from the University of Helsinki's, found that puppies fed a non-processed meat-based diet during the first six months of life were significantly less likely to develop chronic gut disease as adults. Raw feeding supports a more diverse and resilient gut microbiome compared to ultra-processed kibble diets.

Why do first meals matter so much for puppies?

The period from two to six months of age is a critical window for puppy microbiome development. The bacteria and nutrients a puppy encounters during this time help train the immune system and establish gut bacterial diversity. Studies show that dietary choices during this window have measurable effects on health outcomes, including allergies, chronic gut disease, and ear infections.

How does raw feeding affect a puppy's immune system?

Around 70–80% of immune cells reside in or around the gut. A diverse gut microbiome, supported by raw, unprocessed food, helps the immune system distinguish harmless substances from genuine threats. Research shows that puppies fed raw food had significantly lower odds of developing allergies and atopic dermatitis as adults compared to kibble-fed puppies.

When should I start raw feeding a puppy?

Raw weaning paste can be introduced from around three weeks of age as a supplement to the mother's milk. From six weeks onwards, puppies can begin eating a complete raw puppy food formula.

What does a healthy puppy microbiome need?

A healthy puppy microbiome benefits from bioavailable protein, natural fats, raw bone (for minerals), organ meat (rich in micronutrients), and a variety of vegetables providing fibre and phytonutrients. This diverse nutritional profile encourages a rich, varied gut bacterial community.

Does the mother's diet affect puppy gut health?

Yes. Studies found that a mother's diet during pregnancy was associated with reduced risk of chronic gut disease and ear infections in her puppies. A raw, nutrient-dense maternal diet helps pass protective microbial signals to offspring in the womb and through milk.

Scientific References

  • Hemida M, Hielm-Björkman A, et al. (2023). The effect of puppyhood and adolescent diet on the incidence of chronic enteropathy in dogs later in life. Scientific Reports, 13, 1830. doi:10.1038/s41598-023-27866-z
  • Hemida M, Hielm-Björkman A, et al. (2023). Early life programming by diet can play a role in risk reduction of otitis in dogs. Frontiers in Veterinary Science, 10. doi:10.3389/fvets.2023.1186131
  • Hemida M, Hielm-Björkman A, et al. (2025). Modifiable early life risk factors for dental calculus in dogs: a retrospective cross-sectional study in Finland. BMC Veterinary Research, 21, 430. doi:10.1186/s12917-025-04885-8
  • Deusch O, et al. (2014). Deep Illumina-Based Shotgun Sequencing Reveals Dietary Effects on the Structure and Function of the Fecal Microbiome of Growing Kittens. PLOS One. doi:10.1371/journal.pone.0101021 (PMC4091873)
  • Journal of Veterinary Internal Medicine (2025/2026). Longitudinal study of diet digestibility, microbiome, and gut health in dogs aged 2–14 months. doi:10.1111/jvim.16211
  • Bermingham EN, et al. (2015). A Longitudinal Study of the Feline Faecal Microbiome Identifies Changes into Early Adulthood Irrespective of Sexual Development. PLOS One. doi:10.1371/journal.pone.0144881 (PMC4682054)
  • Gavois E, et al. (2022). The Kitty Microbiome Project: Defining the Healthy Fecal "Core Microbiome" in Pet Domestic Cats. Veterinary Sciences, 9(11), 635. doi:10.3390/vetsci9110635