The scores
Blue Buffalo Life Protection Indoor Health: B (75/100) — Deboned Chicken, Chicken Meal, Brown Rice, Barley, Oatmeal.
Hill's Science Diet Adult Indoor Chicken: C (58/100) — Chicken, Whole Grain Wheat, Corn Protein Meal, Powdered Cellulose, Chicken Fat.
How the ingredients compare
Here are the first five ingredients on each label — the part of the panel that drives most of the score under our published rubric:
Blue Buffalo: Deboned Chicken, Chicken Meal, Brown Rice, Barley, Oatmeal
Hill's Science Diet: Chicken, Whole Grain Wheat, Corn Protein Meal, Powdered Cellulose, Chicken Fat
Both foods open with a named fresh chicken, which the rubric rewards. The split comes immediately after. Blue Buffalo follows Deboned Chicken with Chicken Meal — a concentrated, named meat protein — then brown rice, barley, and oatmeal, all whole grains, with no corn, wheat, soy, or by-products in the first five. Hill’s follows Chicken with Whole Grain Wheat, then Corn Protein Meal, then Powdered Cellulose. The rubric applies penalties to wheat, to corn protein meal (a plant-protein concentrate), and to powdered cellulose (a purified insoluble-fiber bulking agent), and those three back-to-back deductions are what separate a B from a C. Blue Buffalo also adds a second meat protein early via chicken meal, where Hill’s reaches a named fat (chicken fat) only in the fifth slot after the fiber. That difference in what fills positions two through five drives the 17-point gap between 75 and 58.
Where Blue Buffalo pulls ahead
Two named chicken proteins up front: Blue Buffalo opens with Deboned Chicken followed immediately by Chicken Meal, stacking a fresh named protein and a concentrated named meat meal in the first two slots. The rubric rewards both: deboned chicken signals real muscle meat, and chicken meal is dense, named protein with the water already removed. Hill’s leads with Chicken but does not reach a second meat protein in its first five — instead it follows with wheat, corn protein meal, and cellulose before arriving at chicken fat. That structural difference, two animal proteins early versus one, is a core reason Blue Buffalo lands in the B band. It is a reproducible, panel-level advantage rather than a marketing claim, and it directly reflects the rubric’s preference for named meat over plant-protein concentrates and fiber fillers in the leading positions. Shop on Amazon →
Whole grains instead of penalized fillers: After its protein lead, Blue Buffalo fills positions three through five with brown rice, barley, and oatmeal — whole grains the rubric treats far more favorably than the wheat, corn protein meal, and powdered cellulose occupying the same slots in Hill’s. Just as important is what Blue Buffalo leaves out: no corn, wheat, soy, or by-product meals appear in the first five. The rubric penalizes corn protein meal as a plant-protein concentrate and powdered cellulose as a purified-fiber bulking agent, and avoiding both keeps Blue Buffalo’s deductions low. This is the single biggest contributor to the 17-point spread. It is not that Blue Buffalo’s grains are exotic — they are ordinary whole grains — but ordinary whole grains simply score better than the filler-and-concentrate tail Hill’s uses to hit its indoor fiber target.
Cleaner named-protein lead plus LifeSource Bits: Blue Buffalo’s win is fundamentally about a cleaner first five: named animal protein up front, recognizable whole grains behind it, and no corn, wheat, soy, or by-products. The brand also includes its signature LifeSource Bits, a cold-formed blend of vitamins, minerals, and antioxidants. The rubric grades the core panel rather than awarding bonus points for proprietary blends, so the Bits are not why Blue Buffalo scores a 75 — the named-protein-forward, filler-light ingredient list is. At roughly $2.00 to $2.60 per pound with wide retail availability, it is also broadly accessible. None of this makes Hill’s a bad food; it means that on the specific axis this rubric measures, the ingredient panel, Blue Buffalo’s composition is the stronger one and earns the higher band on its own merits.
Where Hill's Science Diet holds its own
Functional fiber for indoor cats: The powdered cellulose that costs Hill’s on the rubric is genuinely functional for its intended job. Powdered cellulose is a purified insoluble fiber, and in indoor-cat formulas it is commonly used to help move ingested hair through the digestive tract and to add low-calorie bulk that supports weight control in less active, indoor cats. The rubric penalizes it as a bulking agent because it displaces more nutrient-dense ingredients, and that penalty is part of why Hill’s lands at a C. But the penalty is about ingredient value, not about whether the fiber works — for a sedentary indoor cat prone to hairballs or weight gain, that insoluble fiber is doing a deliberate, useful thing. It is fair to weigh that functional intent against the panel score rather than treating cellulose as purely a negative. Shop on Amazon →
Vet recommendation and feeding-trial substantiation: Hill’s holds real strengths the rubric does not measure. It is the #1 vet-recommended brand, and its diets are substantiated through AAFCO feeding trials — meaning cats were actually fed the food to confirm nutritional adequacy, a more rigorous bar than formulating to a nutrient profile on paper alone. Many owners and veterinarians value that track record and the batch-to-batch consistency Hill’s is known for. None of that changes the ingredient panel, which is what produces the C (58/100), but it is a legitimate reason a buyer might still choose Hill’s. The rubric grades the list of ingredients, not clinical reputation or testing methodology, so a lower panel score and a strong veterinary standing can coexist — and for some households, the substantiation matters more than the panel.
Indoor-specific design and a therapeutic ecosystem: Hill’s Adult Indoor Chicken is purpose-built for indoor cats, with formulation choices — including that insoluble cellulose fiber — aimed squarely at hairball and weight management for less active animals. Beyond this single food, Hill’s anchors a large therapeutic and prescription ecosystem, which means a cat that later develops a medical need (urinary, renal, weight, or digestive) can often transition within the same brand family under veterinary guidance. That continuity has real value for some owners, even though it sits entirely outside what the ingredient rubric scores. At roughly $2.50 to $3.30 per pound, Hill’s is priced above Blue Buffalo, but the indoor-specific design and the breadth of the therapeutic line are genuine reasons it holds its own — the C reflects the panel, not the brand’s overall fit for medically managed cats.
The bottom line
On the ingredient panel, Blue Buffalo Life Protection Indoor Health at B (75/100) clearly outscores Hill’s Science Diet Adult Indoor Chicken at C (58/100) — a 17-point gap. Blue Buffalo earns it with two named chicken proteins up front and whole grains behind them, no corn, wheat, soy, or by-products. Hill’s leads with chicken but then stacks whole grain wheat, corn protein meal, and powdered cellulose, the rubric penalties that cap it at a C. Be clear about what that does and does not mean: Hill’s is the #1 vet-recommended brand, its cellulose is functional for indoor hairball and weight control, and it is feeding-trial substantiated with a deep therapeutic line. The rubric grades the panel, not reputation. Pick Blue Buffalo for the cleaner named-protein lead and the higher score at roughly $2.00 to $2.60 per pound. Pick Hill’s if vet guidance, feeding-trial substantiation, and access to its prescription ecosystem outweigh the panel-level difference.