You buy your cat food labeled "high-protein," pour it into the bowl, and your kitty crunches away with gusto. There's protein, the cat is eating — everything's fine, right? Not necessarily. Because "how much protein is in the food" is only half the equation. The other half is: how much of that protein does your cat actually absorb?
Science has the answer. And it's surprising.
What is digestibility, and why does it matter?
Digestibility is the percentage of a nutrient that the body actually absorbs from the digestive tract — as opposed to what passes through in transit and ends up in the litter box.
If a food contains 40% protein but the digestibility of that protein is 80%, your cat absorbs the equivalent of 32% protein. The rest — 8% — passes through undigested.
Now imagine a different food with 35% protein but 95% digestibility. Your cat absorbs 33.25% — more than from the "high-protein" food with lower digestibility.
That's why digestibility matters more than the declaration on the label alone. And that's why it's worth asking: how does the form of the food — raw meat, cooked meat, dry food — affect how many nutrients your cat actually receives?
We analyzed five scientific studies that answer this question.
Study 1: Kerr et al. 2012 — domestic cats
Full title: Apparent total tract energy and macronutrient digestibility and fecal fermentative end-product concentrations of domestic cats fed extruded, raw beef-based, and cooked beef-based diets. Journal of Animal Science, 90(2):515-522.
Design
Nine adult female domestic cats. They used a so-called crossover study (in a Latin-square design) — each of the nine cats ate diet A for 21 days, then B, and finally C. This meant no cat was stuck on a single food, and the researchers could be sure that the digestibility results came from the food and not from the fact that, say, Mittens the cat naturally has worse digestion than the rest of the group.
Diets compared
- Extruded food (dry): high-protein — 57% protein in dry matter
- Raw beef: raw beef meat — 53% protein
- Cooked beef: the same meat cooked to 71°C — 52% protein
The extruded food in this study had more protein than typical dry food (25-35%). So the comparison was deliberately "fair" in favor of kibble.
Results — digestibility
| Parameter | Raw beef | Cooked beef | Extruded food |
|---|---|---|---|
| Dry matter | ~87% | ~87% | ~78% |
| Crude protein | ~93% | ~93% | ~82% |
The difference in protein digestibility: about 11 percentage points in favor of meat (p ≤ 0.05).
11 pp
Meat vs extruded food in the same cats, in the same lab. A difference of eleven percentage points — not from one day to the next, but on every day of its life.
Raw and cooked beef gave identical results. Zero difference. Cooking to a safe temperature (71°C) didn't lower digestibility by even a percentage point. The authors' conclusion: the problem doesn't lie in "raw vs cooked" — the problem lies in the extrusion process.
Additional data from the litter box and gut
- Stool consistency: on the veterinary scale (1 = hard pebbles, 5 = watery diarrhea, 3 = ideal formed shape) — dry food 3.3 (looser), raw 2.8-2.9, cooked 2.9 (ideal). All results within the healthy range.
- SCFAs (short-chain fatty acids): the good, beneficial acids that nourish the gut wall — no differences between diets.
- BCFAs (branched-chain fatty acids): higher on the meat diet — a natural phenomenon when gut bacteria digest protein instead of carbohydrates.
Study 2: Hamper et al. 2016 — kittens
Full title: Apparent nutrient digestibility of two raw diets in domestic kittens. J Feline Med Surg, 18(12):991-996.
Design
Six domestic kittens (20-28 weeks), crossover design, three diets:
- Canned (cooked): Evo Turkey and Chicken Formula
- Commercial raw: Wild Kitty Raw All Natural Chicken and Clam
- Homemade raw: raw chicken breast + TCFeline Plus supplement
Results — digestibility
| Parameter | Homemade raw | Commercial raw | Canned (cooked) |
|---|---|---|---|
| Dry matter | 92.6% | 90.6% | 83.8% |
| Protein | 97.7% | 94.7% | 88.9% |
| Fat | 93.9% | 96.9% | 94.2% |
97.7%
The highest protein-digestibility result of all five studies. Practically all the protein is absorbed — from home-prepared raw chicken with a supplement.
Even wet food (canned) lost to raw meat by 6-9 percentage points in protein digestibility. Fat was well digested across all variants.
Study 3: Wang et al. 2024 — Ragdoll cats
Full title: Effects of Different Processed Diets on Growth Performance, Blood Parameters, Hair Quality and Fecal Microbiota in Ragdoll Cats. Animals (Basel), 14(18):2729.
Design
Fifteen healthy male Ragdolls (5 months old, 5 per group).
Diets compared
- Extruded food: commercial dry food
- Cooked meat: meat cooked at 81°C for 10 hours
- Raw meat: an unprocessed raw meat product
Results — digestibility
| Parameter | Raw meat | Cooked meat | Extruded food |
|---|---|---|---|
| Dry matter | 85.80% | 90.93% | 81.45% |
| Protein | 94.67% | 96.58% | 89.97% |
| Fat | 95.28% | 96.33% | 92.93% |
This is the only study in which cooked meat beat raw on digestibility — though the difference is small (96.58% vs 94.67%). Both formats outclass kibble.
Stool consistency (scale 1-5, where a higher value = drier stool): kibble 4.58, raw meat 3.54, cooked 3.58. The stool of cats on dry food was unnaturally hard — the result of a huge dose of indigestible fiber and an extreme lack of moisture.
Study 4: Crissey et al. 1997 — sand cats
Eight sand cats (Felis margarita) — small wild felids from the deserts of Africa and Asia. Raw meat was compared with dry food.
Protein digestibility from raw meat: 92.4%, from dry food: 77.9%. The difference: a full 14.5 percentage points — the largest in all five studies. This shows that wild felids may have a digestive system even more strongly programmed for raw meat.
Study 5: Vester et al. 2010 — African wildcats
Five African wildcats (Felis lybica) — the ancestors of all domestic cats. They were given raw meat and a high-protein dry food (>50% protein).
Protein digestibility was significantly higher on the raw-meat diet. Later analyses are more precise: digestibility from raw meat was a full 8 percentage points higher than from extruded food.
The big table: protein digestibility across all studies
| Study | Species | Raw meat | Cooked meat | Dry/canned food | Difference |
|---|---|---|---|---|---|
| Kerr 2012 | Domestic cat | ~93% | ~93% | ~82% | +11 pp |
| Hamper 2016 | Domestic kittens | 94.7-97.7% | — | 88.9% (canned) | +6-9 pp |
| Wang 2024 | Ragdoll | 94.67% | 96.58% | 89.97% | +5-7 pp |
| Crissey 1997 | Sand cat | 92.4% | — | 77.9% | +14.5 pp |
| Vester 2010 | African wildcat | Higher | — | Lower | +8 pp |
Raw meat has 5 to 15 percentage points higher protein digestibility than dry food. In every study. Without exception.
— The consensus of five studies, 1997-2024
Why does extrusion lower digestibility?
Extrusion is the industrial method of producing dry kibble. A meat-and-grain dough is baked in a giant pressure cooker under enormous pressure, at infernally high temperatures (up to 200°C). The cooked mass is then forced through a die that gives it the shape of little rings or fish. Finally, the kibble is dried bone-dry and liberally sprayed with fat and palatants, without which a cat wouldn't recognize it as food at all.
What happens to the protein during all this?
1. The Maillard reaction (browning)
Amino acids react with sugars at high temperatures. Bonds form that the feline digestive system can't break down. The result: the protein is locked inside an armor that the cat's gastric juices can't force open. Losses of the precious amino acid lysine reach up to 80%.
2. Denaturation under pressure
Extrusion is the physical compression and stretching of proteins. A protein's altered shape means worse digestibility.
3. AGEs and HMF — advanced glycation products
It sounds complicated, but these are simply "junk" molecules that form when proteins, under extremely high temperatures, collide and stick together with sugars (the same process that creates the browned crust on bread and fries). The cat's body can't make use of these clumps. Worse, they begin to accumulate in tissues.
38× more HMF than a human
Relative to body weight, cats fed exclusively on dry food consume on average as much as 38 times more HMF than the daily intake of an average adult human. The cat's body has defense mechanisms, but constantly clearing out these unnatural substances is a needless, daily burden on the feline liver and kidneys.
Over the years, such molecules can accumulate in tissues and promote hidden, chronic inflammation that slowly wears down the body and accelerates its aging.
And what about cooked meat?
This is one of the most interesting findings: cooked meat has digestibility comparable to or even slightly higher than raw.
Gentle cooking (71-81°C) denatures proteins just enough that digestive enzymes can reach them more easily, but it doesn't destroy them as aggressively as extrusion. That's good news for people who want excellent nutrition but are wary of raw meat on microbiological grounds. BACF (Biologically Appropriate Cooked Food) is perfectly safe for our cats.
What does this mean in practice?
1. A cat on dry food needs MORE food
If protein digestibility in dry food is 82% and in raw meat 93%, a cat on kibble has to eat about 13.4% more food to get the same dose of protein. More food = more calories = a higher risk of obesity.
2. A higher percentage on the package is only theory
Food labeled "57% protein" with low digestibility gives a cat less real nutrition than raw meat that has 53% protein on paper. The label doesn't tell the whole truth about absorbability.
3. Surprising health differences (Wang 2024)
- Coat: under the microscope, the hair scales of cats on meat were smooth and undamaged; on kibble — frayed and degraded.
- MDA (a marker of oxidative damage): less cellular damage on meat. The body of a meat-fed cat "rusts" from the inside far more slowly.
- Globulins: a significantly higher level in cats on the meat diet signals a stronger immune shield and fewer infections.
4. The litter-box matter
The poop of cats on a meat diet usually lands at the "ideal" point on veterinary scales (a value of ~3.0 — firm, small, hassle-free to clean up). Because of the lack of digestibility of kibble and the fiber that swells inside it, cats on dry food pass stools that are larger in volume and often downright too dry.
5. BARF requires balancing
Digestibility isn't everything
High digestibility doesn't exempt you from balancing. A meat-based diet must be supplemented with the right additions (calcium, vitamins, taurine). Without them, it's a straight road to deficiencies. Check it in the calculator — it automatically calculates Ca:P, taurine, and 12 categories of supplements.
To be fair: the limitations of these studies
It would be dishonest not to mention the scientific limitations: small study groups (5-15 cats), short durations (up to 35 days per diet), comparing different protein sources (poultry vs beef), and the fact that some of them involved wild felids.
Despite these limitations, the direction of the results is unambiguous across all five studies, which gives them enormous credibility.
Summary
Five studies, three species, three decades of science. The result is the same every time: raw and cooked meat have 5 to 15 percentage points higher protein digestibility than dry food. The problem lies in the industrial production of kibble (extrusion).
If you decide to feed meat (BARF/BACF), always remember to balance it wisely. Our BARF calculator will handle the math for you — automatically balancing calcium, taurine, and vitamins on the basis of thousands of data points, so your cat gets food that's not only the most digestible but also perfectly matched to its evolutionary needs.
Sources
- Kerr K.R., Vester Boler B.M., Morris C.L., Liu K.J., Swanson K.S. Apparent total tract energy and macronutrient digestibility and fecal fermentative end-product concentrations of domestic cats fed extruded, raw beef-based, and cooked beef-based diets. J Anim Sci. 2012; 90(2):515-522. PMID: 22003235.
- Hamper B.A., Kirk C.A., Bartges J.W. Apparent nutrient digestibility of two raw diets in domestic kittens. J Feline Med Surg. 2016; 18(12):991-996. PMC 11112242.
- Wang P., Tian X., Feng J. Effects of Different Processed Diets on Growth Performance, Blood Parameters, Hair Quality and Fecal Microbiota in Ragdoll Cats. Animals (Basel). 2024; 14(18):2729. PMC 11429482.
- Crissey S.D., Swanson J.A., Lintzenich B.A., Brewer B.A., Slifka K.A. Use of a raw meat-based diet or a dry kibble diet for sand cats (Felis margarita). J Anim Sci. 1997; 75(8):2154-60. PMID: 9263063.
- Vester B.M., Burke S.L., Liu K.J., Dikeman C.L., Simmons L.G., Swanson K.S. Influence of feeding raw or extruded feline diets on nutrient digestibility and nitrogen metabolism of African wildcats (Felis lybica). Zoo Biology. 2010; 29(6):753-61. PMID: 20095004.
- Does the definition of human ultra-processed foods apply to dog and cat foods? Frontiers in Veterinary Science. 2026. DOI: 10.3389/fvets.2026.1690420.
Frequently asked
What is digestibility, and does it matter more than the "% protein" on the label?
Digestibility is the percentage of a nutrient that the body actually absorbs from the digestive tract. Food with 35% protein and 95% digestibility gives a cat more real nutrition than food with 57% protein and 82% digestibility. The label doesn't tell the whole truth.
Is cooked meat worse than raw?
No. Five studies show that gentle cooking (71-81°C) gives digestibility comparable to or even slightly higher than raw. That's good news for people wary of raw food on microbiological grounds — BACF (Biologically Appropriate Cooked Food) is safe and highly digestible.
Why does extruding kibble lower protein digestibility?
In extrusion, a meat-and-grain mass is baked under pressure at temperatures up to 200°C. This triggers the Maillard reaction (up to 80% lysine loss), denaturation under pressure, and the formation of AGEs and HMF — products the cat's body can't use and that burden the liver and kidneys.
Does a cat on dry food eat more?
Yes. If protein digestibility in kibble is 82% and in raw meat 93%, a cat on kibble has to eat ~13% more to get the same dose of absorbable protein. More food = more calories = a higher risk of obesity.
