What's actually in Royal Canin?
We analyzed Royal Canin Indoor Adult Dry Cat Food, one of the brand's most popular products for indoor cats. The first five ingredients are chicken by-product meal, brewers rice, corn, wheat gluten, and corn gluten meal.
Chicken by-product meal at number one sounds vaguely protein-forward, but by-product meal is a rendered product made from organs, necks, feet, and other parts not used for human consumption. It's concentrated protein, yes, but it's the cheapest form of animal protein a manufacturer can use. Brewers rice at number two is a milling fragment — essentially broken rice pieces left over from processing. Corn at number three is a filler carbohydrate that cats have no biological need for. Wheat gluten at number four and corn gluten meal at number five are plant-based protein concentrates used to inflate the protein percentage on the label without adding actual meat. Cats are obligate carnivores. A formula where four of the top five ingredients are grains and plant proteins is fundamentally misaligned with feline nutritional needs.
Further down the list, chicken fat provides essential fatty acids, and natural flavors is a vague palatability enhancer. Dried plain beet pulp is a fiber source, and powdered cellulose is essentially wood pulp — an indigestible bulking agent often used in "indoor" formulas to reduce stool volume. Shop on Amazon →
The good stuff
Royal Canin does include a few genuinely positive ingredients. Fish oil provides omega-3 fatty acids (EPA and DHA) that support skin, coat, and joint health — a quality addition that many cheaper brands skip entirely. Psyllium seed husk is a soluble fiber that supports digestive regularity and may help with hairball management, which is relevant for indoor cats.
Taurine is supplemented, which is essential — cats cannot synthesize it on their own, and a deficiency can cause blindness and heart disease. L-carnitine supports fat metabolism, a useful addition for less-active indoor cats prone to weight gain. Rosemary extract serves as a natural preservative, which is preferable to artificial alternatives like BHA or BHT.
Royal Canin also invests heavily in feeding trials and veterinary research. The company employs board-certified nutritionists, and their formulas are tested in controlled settings — not just formulated on paper. This is a legitimate advantage over brands that only meet AAFCO minimums through calculation.
The not-so-good stuff
The core problem is simple: this is a grain-and-plant-protein food marketed as premium cat nutrition. Corn at number three and corn gluten meal at number five mean corn appears twice in the top five — a classic ingredient-splitting concern where a single cheap ingredient is listed under multiple names to prevent it from appearing first. Wheat gluten at number four is another plant protein inflating the protein percentage. When you see this many plant proteins in a cat food, the guaranteed analysis might look adequate, but the amino acid profile is not what an obligate carnivore needs.
Powdered cellulose is essentially sawdust. It's an indigestible fiber used to add bulk without calories, and while it has some legitimate use in weight management formulas, it's a cheap filler in a food at this price point. "Natural flavors" is a vague catch-all — it could be almost anything, and Royal Canin doesn't specify further.
The price is the final insult. Royal Canin Indoor Adult typically costs $3–4 per pound, putting it in the same range as brands like Wellness (B/80) and Taste of the Wild (B/76), which have dramatically better ingredient lists. You are paying premium prices for a formula built on by-product meal, corn, and wheat gluten.
How it compares
Royal Canin's D/45 is one of the lowest scores in our cat food database. It sits below Iams (C/62), Purina Pro Plan (C/56), and Hill's Science Diet (C/60) — all of which cost less. That's a remarkable outcome: one of the most expensive cat foods on the market scores lower than three mid-priced competitors.
Blue Buffalo (B/76) scores 31 points higher at a comparable price. Even Purina ONE (D/52), which costs roughly half as much, manages a higher score. The only cat foods that score lower than Royal Canin in our database are the budget basement options: Meow Mix (F/18) and Friskies (D/37).
The exception, as with the dog formulas, is Royal Canin's Veterinary Diet line — those are therapeutic products prescribed for specific medical conditions and are a different conversation entirely.
Read the full breakdowns in our head-to-head comparisons: Hill's Science Diet vs Royal Canin and Purina ONE vs Royal Canin.
The bottom line
Royal Canin Indoor Adult earns a D grade (45/100) from KibbleIQ. The fish oil, psyllium seed husk, taurine supplementation, and natural preservatives are genuinely good additions. But chicken by-product meal as the lead ingredient, double corn in the top five, wheat gluten as a plant protein filler, and powdered cellulose as bulk — all at a premium price — make this one of the worst values in cat food. The vet recommendation carries weight, and Royal Canin's research infrastructure is real. But the ingredient list tells a different story than the marketing. For everyday feeding, your money buys significantly better nutrition elsewhere. Shop on Amazon →