What does biologically appropriate mean?

January 10, 2026 •

4 min read

According to the principles of evolutionary biology, an animal's diet should align with what its ancestors naturally consumed. But what does biologically appropriate mean, and why is this concept becoming a focus for pet owners seeking optimal health for their companions? This feeding philosophy centers on natural dietary needs rather than simply convenient processed foods.

Quick Summary

The biologically appropriate feeding concept revolves around providing a diet that aligns with an animal's evolutionary requirements, prioritizing species-specific whole foods like meat, organs, and bones over processed fillers for enhanced nutrient absorption and overall wellness.

Key Points

Evolutionary Alignment: The core of a biologically appropriate diet is mimicking the natural, ancestral diet of a specific animal species.
High Animal Protein: For carnivorous pets like dogs and cats, this means a diet rich in high-quality animal proteins, including muscle meat, organs, and bones.
Low Carbohydrate Content: Unlike many commercial pet foods, biologically appropriate diets avoid cheap fillers like grains and other unnecessary carbohydrates.
Minimal Processing: Nutrients are provided in their natural, bioavailable form through raw, freeze-dried, or minimally processed whole foods.
Species Specificity: The exact diet varies significantly between species; for instance, cats are obligate carnivores while dogs are more omnivorous.
Not One-Size-Fits-All: While beneficial for many, owners should always consult a veterinarian before a major diet change, especially for pets with pre-existing conditions.

Defining Biologically Appropriate Nutrition

Biologically appropriate nutrition, also known as a species-appropriate diet, refers to feeding an animal in a way that matches its natural, evolutionary dietary needs. This involves mimicking the types of food an animal's ancestors would have consumed in the wild. The theory suggests that an animal's digestive system, physiology, and anatomy are best suited to process and thrive on this kind of diet, which often consists of raw, minimally processed, and whole-food ingredients. The goal is to provide nutrients in their most bioavailable form, meaning they are more easily absorbed by the body.

The Biologically Appropriate Diet for Dogs

For dogs, the biologically appropriate diet is modeled after their closest wild relatives, the wolf, but with an understanding of their omnivorous scavenging evolution. A biologically appropriate dog diet typically includes:

High-quality animal protein: Primarily muscle meat, organs, and bones.
Low carbohydrates: Minimal or no grain content, avoiding the cheap fillers found in many kibbles.
Fruits and vegetables: Ground plant matter that provides beneficial vitamins, minerals, and phytonutrients, mimicking the gut content of prey.
Minimal processing: Raw or freeze-dried formats that preserve the natural enzymes and nutrients lost in cooking.

The Biologically Appropriate Diet for Cats

Cats, unlike dogs, are obligate carnivores, meaning their diet must consist almost entirely of animal-derived food. A biologically appropriate diet for a cat is therefore even more heavily meat-focused:

Very high animal protein: At least 95% animal-derived ingredients, including muscle meat and organs.
High moisture content: Important for cats who have a low thirst drive, helping to support kidney and urinary tract health.
Raw meaty bones: Providing essential calcium, phosphorus, and dental benefits, though care must be taken with size and type.
No grains or carbohydrates: A cat's digestive system is not designed to process grains, and high-carb diets can lead to health issues.

Benefits of Biologically Appropriate Feeding

Switching to a biologically appropriate diet can lead to several noticeable health improvements for pets:

Improved Digestion: The high digestibility of natural ingredients results in smaller, firmer stools and fewer issues with bloating or gas.
Healthier Skin and Coat: A diet rich in high-quality animal proteins and essential fatty acids promotes a shinier, softer coat and healthier skin.
Optimal Weight Management: Raw, low-carb diets help pets maintain a healthy weight and avoid obesity, which is a common problem with processed foods.
Increased Energy and Vitality: When pets receive nutrition that their bodies are designed to use, they often exhibit higher energy levels and a more active, playful demeanor.
Better Dental Health: For raw diets, chewing on raw meaty bones can act as a natural toothbrush, reducing plaque and tartar buildup.

Biologically Appropriate vs. Commercial Kibble

This table highlights the key differences between a typical commercial kibble diet and a biologically appropriate raw diet.


Feature	Commercial Kibble	Biologically Appropriate (BARF/Raw)
Processing Level	High heat processing and extrusion.	Minimal or no cooking; often raw or freeze-dried.
Primary Ingredients	Often high in cheap fillers like grains, cereals, and plant-based protein.	High percentage of animal protein, including muscle meat, organs, and bones.
Nutrient Quality	Nutrients can be degraded by heat, requiring synthetic vitamin and mineral supplementation.	Bioavailable nutrients from whole foods; vitamins and minerals are natural.
Moisture Content	Very low moisture content, requiring pets to drink more water.	High moisture content, aiding hydration and kidney function.
Digestibility	Can be difficult to digest for some pets, leading to larger, softer stools.	Highly digestible, leading to smaller, firmer stools.
Cost	Generally more affordable upfront.	Can be more expensive due to higher-quality ingredients.

Potential Risks and Safe Transition

While advocates praise the benefits, biologically appropriate feeding, especially raw food, requires careful management to mitigate risks. Raw meats can carry bacteria like Salmonella or E. coli that, while a carnivore's digestive system is better equipped to handle, can still pose a risk to both the pet and human handlers. To ensure safety, proper handling and storage of raw ingredients are crucial. When switching your pet's diet, a gradual transition over 7 to 10 days is recommended to prevent digestive upset. As with any significant dietary change, it is wise to consult with a veterinarian, especially if your pet has existing health conditions.

Conclusion

Ultimately, understanding what does biologically appropriate mean empowers pet owners to make informed choices that prioritize their pet's health based on their natural, evolutionary needs. By focusing on high-quality, minimally processed, species-specific ingredients, this feeding philosophy can lead to better digestion, healthier skin and coat, and enhanced vitality. While requiring careful preparation and sourcing, a biologically appropriate diet provides a way to feed pets in a manner that truly aligns with their innate biology, supporting their long-term health and well-being. For further reading, Dr. Ian Billinghurst's work is a foundational resource on the BARF diet and the philosophy behind biologically appropriate feeding.

Frequently Asked Questions

Biologically appropriate is the overarching concept of feeding a species according to its natural diet, while raw feeding is one method of achieving that. Raw feeding, such as the BARF diet, uses raw, whole foods to create a biologically appropriate meal plan.

No. While both involve species-specific foods, cats are obligate carnivores requiring a much higher percentage of animal protein, with minimal to no plant matter. Dogs, as omnivorous scavengers, benefit from a higher meat content but can also digest some plant-based ingredients.

While cooking some whole foods is healthier than highly processed kibble, the term 'biologically appropriate' generally refers to raw or minimally processed foods that retain their natural enzymes and nutrients. Cooking denatures some nutrients and enzymes that would be available in a raw, ancestral diet.

Common benefits include improved digestion, healthier skin and coat, better weight management, increased energy levels, and improved dental hygiene from chewing raw bones.

The cost can be higher than conventional kibble due to the use of higher-quality, whole-food ingredients like fresh meat, organs, and bones. However, some owners feel the long-term health benefits can offset future veterinary costs.

To transition safely, it is recommended to introduce the new food gradually over 7 to 10 days, mixing a small amount with their current food and slowly increasing the proportion. This helps prevent digestive upset.

BARF stands for 'Biologically Appropriate Raw Food' or 'Bones and Raw Food.' It is a specific model of raw feeding that includes raw meat, edible bones, vegetables, fruits, and other ingredients.

Yes, there is a risk of bacterial contamination from pathogens like Salmonella or E. coli, which can affect both pets and humans. However, this risk can be minimized through proper handling, sourcing, and hygiene practices, and consulting with a vet.