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Fat in dog and cat diets

A short guide to the role of Fat in dog and cat nutrition.

Fat

Fat is the most concentrated source of energy in the diet — it provides more than twice as many calories as protein or carbohydrates (9 kcal/g versus 4 kcal/g), so even a small change in its amount significantly affects the calorie content of the mixture [1]. Besides energy, fat is a carrier of vitamins A, D, E and K (without it they will not be absorbed even with a sufficient supply), a building block of cell membranes, and the foundation of healthy skin and coat. An important distinction: the amount of fat alone says nothing about the fatty acid profile — a diet can have enough fat and at the same time zero EPA and DHA.

Where it's found: You regulate fat primarily by the choice of cuts of meat, not by separately "adding fat" [1]. Fattier options: pork neck, jowl, poultry wings and thighs with skin, hearts, mutton, salmon. Leaner: turkey breast, venison, lean beef. The fats of land animals provide mainly omega-6 (linoleic acid) and energetically neutral omega-9 — but cover long-chain omega-3 very poorly, which must be sought in small fatty sea fish (sardines, sprats, herring) and fish oil.

Deficiency: Dry, flaky skin and a dull, brittle coat are usually the first symptom; further on slower wound healing, in the young a stunting of growth, and with chronic deficiency a weakening of immunity [1] [2]. In practice it happens when the owner obsessively chooses only lean meats out of fear of obesity — this is a mistake, because one should limit total calories, not fat itself.

Excess: The most common real problem is obesity, because fat is very caloric [3]. The second, equally important mechanism is the "dilution" of the diet: on a too-fatty mixture the animal satisfies its calorie needs faster, eats fewer total grams and automatically gets too little protein, minerals and vitamins [1]. If the calculator shows good fat coverage but deficiencies of protein or minerals — the first thing to check is whether there is not too much fat.

Species difference

In dogs, sudden, large jumps in the amount of fat (e.g. a large portion of fatty scraps after a period of lean feeding) can trigger acute pancreatitis, especially in predisposed breeds (Miniature Schnauzer, Cocker Spaniel, Yorkshire Terrier) [2]. Gradually increasing fat is usually safe.

In cats — obligate carnivores — fat is, alongside protein, the main fuel and a key carrier of palatability. Pancreatitis is rarer in them and more weakly linked to jumps in fat, but another, serious risk appears: a too-lean, unpalatable diet can make the cat eat too little, and in an overweight cat that stops eating there is a real threat of hepatic lipidosis (fatty liver) — a life-threatening condition [4]. That is why an obese cat is slimmed down by reducing the portion, not by drastically lowering fat. Additionally, the cat needs arachidonic acid directly from animal fats, because it does not synthesize it efficiently on its own [5].

What to watch for

A greater amount of PUFA (fish oil, fatty fish) increases the requirement for vitamin E, which protects these acids from oxidation — if there is a lot of omega-3 in the diet, check the vitamin E coverage [1]. Add fish oil just before serving, not to the whole batch in advance — oxidized (rancid) fats generate free radicals and use up vitamin E. The official minimum fat (AAFCO 2023): about 5.5% of dry matter for adult dogs (8.5% for growth) and about 9% for cats; in practice a raw diet usually lies higher, and the calculator aims at a value matched to the specific animal, not at a rigid percentage [6].

Sources

  1. National Research Council (NRC) (2006). Nutrient Requirements of Dogs and Cats, chapter 6 — fats and fatty acids. https://nap.nationalacademies.org/catalog/10668/nutrient-requirements-of-dogs-and-cats
  2. Hand MS, Thatcher CD, Remillard RL, Roudebush P, Novotny BJ (2010). Small Animal Clinical Nutrition, 5th Edition. https://www.markmorrisinstitute.org/sacn5.html
  3. Lyu Y, Wu C, Li L, Pu J (2025). Current Evidence on Raw Meat Diets in Pets: A Natural Symbol, but a Nutritional Controversy. Animals 15(3):293. https://doi.org/10.3390/ani15030293
  4. Merck Veterinary Manual. Feline Hepatic Lipidosis. https://www.merckvetmanual.com/digestive-system/hepatic-diseases-of-small-animals/feline-hepatic-lipidosis
  5. Today's Veterinary Practice (2016). Role of Dietary Fatty Acids in Dogs & Cats. https://todaysveterinarypractice.com/nutrition/role-of-dietary-fatty-acids-in-dogs-cats/
  6. FEDIAF (2021). Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs. https://europeanpetfood.org/self-regulation/nutritional-guidelines/