With companion animals occupying an increasingly important place in households around the world, the question of how to feed them has become equally significant. What influences pet owners when choosing their pets’ food? This article explores the nutritional needs of the world’s two most popular companion animals and examines what constitutes an appropriate diet for each according to new guidelines.^1,2

The 2024 Global Pet Parent Survey estimates that the global pet population is ~1 billion. Cats and dogs are the most popular. Cats appear to be slightly more popular among men, with 52% of male respondents owning cats compared with 48% of women.The United States was identified as the world’s most pet-friendly country, followed by Canada, Brazil, India, South Africa and New Zealand.¹

What influences what ends up in their bowls?

Research examining pet food purchasing decisions suggests that three major factors play a central role: The characteristics of the food itself, the sources owners rely on for recommendations, and the bond between pets and their owners.²

Among the most important considerations are price, ingredients and quality. Multiple studies have found that ingredients, in particular, rank as one of the leading factors pet owners consider when selecting food for their animals.²

The findings also point to a balancing act among consumers. While pet owners appear to favour more affordable food options, they also place considerable value on products containing natural and organic ingredients.²

Although commercial pet food remains the most common choice for many households, owners do not necessarily rely on it exclusively. A significant number supplement commercial diets with other foods, including home-prepared meals, table scraps and raw meat-based diets.²

Recommendations also play an important role in shaping feeding choices, with research consistently identifying veterinarians as the primary source of pet nutrition information for consumers. However, the Internet and social media have increasingly become influential sources of information — and misinformation — about pet nutrition.²

What’s in the bowl? The five nutrients every pet needs

The nutritional needs of cats and dogs vary according to life stage, health, activity and individual circumstances. The 2025 European Pet Food Industry Federation guidelines provide recommended minimum and maximum nutrient levels for commercial foods intended for healthy cats and dogs, based on ingredients with normal digestibility and average bioavailability. The guidelines stress that water should always be freely available, while feeding frequency and quantities should follow the requirements of the pet and the product.³

The guidelines also distinguish between complete and complementary pet food. Complete food is formulated to provide all the nutrients required for a particular species and physiological state when fed as the sole diet. Complementary foods, including treats, are intended to form only part of the diet and must be combined with other foods to provide a nutritionally adequate daily ration (see Table 1).³

Cats and dogs require five key nutrients, in addition to water: Protein, carbohydrates, fats, vitamins and minerals. Protein, carbohydrates and fats provide energy, while also performing important structural and physiological functions.³

Protein supplies essential amino acids and provides the building blocks for muscles, organs, bones, blood, the immune system and hair. Cats require 11 essential amino acids and dogs 10. Protein sources can be animal- or plant-based, but both the amount and digestibility of protein are important. Providing more protein than an animal requires does not result in additional muscle development or health benefits.³

Carbohydrates provide readily available energy and can be stored as glycogen in the liver and muscles. While there is no minimum carbohydrate requirement in pet food, carbohydrates provide energy and dietary fibre. Digestible carbohydrates such as starches and sugars support energy metabolism, while fibre contributes to healthy stool quality, gut motility and satiety. Processing through grinding and cooking makes carbohydrates readily digestible.³

Dietary fat provides essential fatty acids, supports cell membranes and hormone production, and enables absorption of vitamins A, D, E and K. Fat also enhances palatability and provides a concentrated source of energy. Omega-3 fatty acids support cell membranes and help reduce inflammation, while omega-6 fatty acids contribute to tissue repair.³

Finally, vitamins and minerals are required in smaller quantities but are essential for numerous bodily functions. Major minerals include calcium, phosphorus, potassium, sodium, chloride and magnesium, while trace elements include iron, copper and selenium. Because cats and dogs cannot produce all the vitamins they need, these must be supplied through their diet.³

Advances in pet nutrition and food technology have made it possible to formulate foods that provide these nutrients in appropriate amounts and proportions, supporting healthier, longer lives for companion animals.³

Older, wiser – but with different nutritional needs

Cats and dogs are living longer, and older pets now make up >50% of the companion-animal population. This growing senior population presents an important nutritional challenge, yet there is still no independent consensus defining specific nutritional requirements for older cats and dogs.⁴

Nutritional strategies should reflect the individual animal’s life stage, body condition, muscle condition, activity and any diagnosed health problems.Ageing is associated with several physiological changes. Cats and dogs tend to gain fat while losing lean muscle mass, with sarcopenia and frailty becoming increasingly important concerns.⁴

Energy requirements often decline with age, particularly in dogs, largely because of reductions in activity and lean body mass. However, simply reducing food intake can inadvertently reduce protein intake. Older animals therefore need sufficient high-quality protein and essential amino acids to preserve lean mass, while total calories should be adjusted to maintain an optimal body condition. In cats, at least 5g of highly digestible protein/kg optimal body weight/day is suggested to support lean mass.⁴

Other nutritional considerations are equally individualised. Long-chain omega-3 fatty acids, particularly eicosapentaenoic acid and docosahexaenoic acid, may support cognitive function and help manage inflammation associated with osteoarthritis. Adequate antioxidants are important when diets are enriched with these fatty acids. Phosphorus deserves particular attention in older animals with kidney disease, but indiscriminate protein restriction is not appropriate simply because a pet is old.⁴

Ageing can also affect appetite, dental health, smell, thirst and gastrointestinal function. Highly palatable, energy-dense foods may benefit animals with poor appetites, while softer or wet foods can help pets with dental problems and increase water intake. Cats may particularly benefit from wet food to support hydration.⁴

The key message is that there is no single ‘senior diet’ that suits every older pet. Nutritional assessment should form part of routine veterinary care, including evaluation of body weight, body condition, muscle mass, dental and gastrointestinal health, urinary health and the complete diet, including treats. Any nutritional changes should then be monitored and adjusted.⁴

For older pets with conditions such as cognitive decline, osteoarthritis, cancer, hyperthyroidism or chronic kidney disease, nutrition becomes part of disease management. The goal remains consistent: Provide enough energy, protein and essential nutrients to maintain health and muscle mass while adapting the diet to the individual animal’s specific needs.⁴

How much is enough? Feeding by the numbers

A useful starting point is the resting energy requirement (RER) – the calories needed to support essential functions such as breathing, circulation, digestion and brain activity. RER can be estimated using body weight (see Table 1), and this figure is then adjusted using factors appropriate to the pet’s life stage and lifestyle to estimate its total daily energy requirement.⁵

These calculations are starting points rather than precise prescriptions. Individual pets can require substantially more or fewer calories than the calculated estimate. Breed can also make a difference (See Table 2): Two dogs of similar size may have very different energy requirements if one is highly active and the other has a more sedentary lifestyle.⁵

The best guide over time is therefore your pet’s body and muscle condition. Start with the estimated daily amount, then adjust the quantity up or down according to whether your pet is maintaining a healthy body condition and muscle mass. Regular reassessment is important because calorie requirements can change with age, activity, health and other circumstances.⁵

In practical terms: Calculate, measure, monitor and adjust. Feeding guidelines and calorie calculations provide a useful starting point, but your pet’s body condition is ultimately a better guide to whether you are feeding the right amount.⁵

Table 1: Estimated daily food requirements for dogs and cats⁵

Body weight (kg)	RER (kcal/day)	Approximate food (g/day)*	Approximate food (cups/day)*
2	118	34–51	⅓–½ cup
3	160	46–69 g	½–¾ cup
4	198	57–85 g	½–¾ cup
5	234	67–100 g	⅔–1 cup
6	268	77–115 g	¾–1¼ cups
7	301	86–129 g	¾–1¼ cups
10	394	113–169 g	1–1¾ cups
15	534	153–229 g	1½–2¼ cups
20	662	189–284 g	2–2¾ cups
25	783	224–336 g	2¼–3⅓ cups
30	897	257–384 g	2½–3¾ cups

*Illustrative only, assuming a dry food containing 2500–3500 kcal/kg. The actual amount depends on the calorie density of the food.

The Goldilocks zone: keeping weight and muscle just right

Maintaining an optimal body weight and preserving muscle mass are central to healthy ageing and longevity (see Table 2 and 3). Excess weight can shorten lifespan and increase the risk of chronic disease, while being underweight can also compromise survival, particularly in animals with chronic disease.⁴

Table 2: Popular dog breed healthy weight range (Examples)⁶

Dog breed	Female weight (kg)	Male weight (kg)
Australian Shepherd	18.1–25	22.7–29.5
Beagle	9.1–10	9.1–10
Boxer	25–29.5	29.5–36.3
Cairn Terrier	5.9–7.3	6.4–7.4
Cane Corso	38.6–45.4	40.8–49.9
Cardigan Welsh Corgis	11.3–15.4	13.6–17.2
Dachshund Standard	7.3–14.5	7.3–14.5
Doberman Pinscher	27.2–40.8	34–45.4
French Bulldog	7.3–10.9	9.1–12.7
German Shepherd	22.6–31.8	29.5–40.8
Great Dane	49.9–63.5	63.5–79.4
Lhasa Apso	5.4–8.2	5.4–8.2
Pembroke Welsh Corgis	10–11.8	11.8–13.6
Poodle Miniature	4.5–6.8	4.5–6.8
Labrador Retriever	25–31.8	29.5–36.3
Golden Retriever	25–29.5	29.5–36.3
Rottweiler	36.3–45.4	43.1–61.2
Shih Tzu	4.1–7.3	4.1–7.3
Clumber Spaniel	25–31.8	27.2–38.6
Yorkshire Terrier	1.8–3.2	1.8–3.2

Note: These are example breed weight ranges. Ideal body weight varies between individual dogs and should be assessed alongside body condition, muscle condition, age and overall health.

Table 3: Cat healthy weight range (examples)⁶

Cat breed	Female weight (kg)	Male weight (kg)
Domestic	3.6–4.5	3.6–4.5
Himalayan	3.2–5.4	3.2–5.4
Maine Coon	4.5–5.8	6.8–11.3
Persian	3.2–5.4	3.2–5.4
Siamese	3.2–4.5	3.2–4.5

Note: These are example breed weight ranges. Ideal body weight varies between individual cats and should be assessed alongside body condition, muscle condition, age and overall health.

5 key messages to share with pet owners

1. Choose a complete, balanced diet appropriate for your pet
Look for a complete food formulated for your pet’s species and life stage. Dogs and cats have different nutritional requirements, and complementary foods and treats should not replace a nutritionally complete diet.

2. Feed the pet, not the label
Feeding guidelines and calorie calculations are useful starting points, but individual energy requirements vary. Measure portions, monitor body weight and body condition, and adjust the amount as necessary.

3. Keep an eye on muscle, not just the scale
Maintaining healthy muscle mass is particularly important as pets age. Weight loss is not always healthy if it comes with loss of lean tissue, so body condition and muscle condition should both be assessed.

4. Be cautious about nutrition advice from social media
Natural, raw, grain-free or homemade diets are not automatically healthier. Ask your veterinarian before making significant dietary changes, particularly if your pet has a medical condition.

5. Reassess nutrition throughout your pet’s life.
There is no single diet or feeding amount that suits every pet forever. Age, activity, body condition, dental health and disease can all change nutritional needs. Regular veterinary nutritional assessments can help ensure the diet continues to meet your pet’s needs.

Conclusion

Nutrition is one of the simplest ways owners can support their pets’ health, but there is no universal diet that suits every dog or cat. The right nutritional approach depends on species, life stage, activity, body and muscle condition, and any underlying disease.

A complete and balanced diet provides the foundation, while appropriate portions, consistent feeding and regular reassessment help maintain a healthy body weight and preserve muscle mass throughout life. Calorie calculations and feeding guidelines provide useful starting points, but the pet itself remains the best guide to whether adjustments are needed.

For older animals, nutritional needs can change as appetite, activity, muscle mass and health status evolve. This makes regular nutritional assessment particularly important. Owners should also be encouraged to look beyond marketing claims and social-media advice and seek veterinary guidance before making major dietary changes.

Ultimately, good nutrition is not about finding the perfect food once. It is about continually adapting the diet to the individual pet, helping dogs and cats remain healthy, active and well nourished throughout their lives.

References

1. Global Pet. Global pet population at 1 billion, cats lead the way. 2024 [Internet]. Available at: https://globalpetindustry.com/news/global-pet-population-at-1-billion-cats-lead-the-way/
2. Schleicher M, Cash SB, Freeman LM. Determinants of pet food purchasing decisions. Can Vet J, 2019.
3. FEDIAF. Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs. 2025 [Internet]. Available at: https://europeanpetfood.org/wp-content/uploads/2025/09/FEDIAF-Nutritional-Guidelines_2025-ONLINE.pdf?
4. Blanchard G, Priymenko N, Oh WS. Nutrition and aging in dogs and cats: assessment and dietary strategies. J Vet Sci. 2025.
5. Veterinary Medical Centre. Companion Animal Nutrition Support Service. [Internet]. Available at: https://vmc.vet.osu.edu/services/companion-animal-nutrition-support-service
6. Association for Pet Obesity Prevention. Pet body condition and healthy weight tools. https://www.petobesityprevention.org/pet-caloric-needs.