"By-product" and "meal" sound like waste and are usually read that way. Both have legal definitions under AAFCO, and both describe concentrated animal tissue that supplies nutrients a cat needs. The word that actually predicts quality is the one in front of them: chicken is a species, poultry is a category, and meat on its own is a shrug.
What the definitions actually say
AAFCO's meat by-products is the non-rendered, clean parts of a slaughtered animal other than meat: lungs, spleen, kidneys, brain, liver, blood, bone, and partially defatted fatty tissue. It excludes hair, horns, teeth, hooves, and the contents of the intestinal tract. Poultry by-products adds heads and feet, which is why the category is cheaper. Meat alone means striated muscle plus the tissue naturally accompanying it.
Meal is a rendering outcome, not a grade. Fresh chicken is roughly 70% water; chicken meal is that same tissue dried and defatted to about 10% moisture, which pushes crude protein past 60%. Ten kilograms of fresh chicken delivers around 3 kg of dry matter and 0.6 kg of protein; 3 kg of chicken meal delivers around 2 kg of protein. Same animal, very different arithmetic on the label.
Organs are the nutrient-dense part
Liver carries vitamin A, iron, copper and folate at concentrations muscle meat does not approach. Heart is one of the richest natural sources of taurine, the amino acid cats cannot synthesise enough of. Kidney supplies B vitamins and selenium. Bone, when it is ground into the mix, is calcium and phosphorus in the form the animal built.
| Tissue | What it brings | Why it matters for a cat |
|---|---|---|
| Liver | Vitamin A, iron, copper, B12 | Cats cannot convert beta-carotene efficiently; preformed A has to come from animal tissue |
| Heart | Taurine, CoQ10, B vitamins | Taurine deficiency causes DCM and retinal degeneration |
| Kidney | Selenium, B2, B12 | Trace minerals that plant matter supplies poorly |
| Ground bone | Calcium, phosphorus, collagen | The calcium a muscle-only diet lacks entirely |
A diet of boneless chicken breast is the classic homemade failure: high protein, zero calcium, wrong calcium-to-phosphorus ratio. Organ meat is not the shortcut version of a good diet. In many formulations it is the part that makes the diet complete.
The word before "meal" is the whole ballgame
- Chicken meal, turkey meal, salmon meal — a named species. Traceable, and the best case on a label.
- Poultry meal, poultry by-product meal — any bird, from any plant, batched together. Legal, common, and impossible to audit.
- Meat meal, meat and bone meal — any mammal. This is the one worth avoiding in a premium-priced food, because the price no longer matches the transparency.
- Animal by-product meal, "animal digest" — the least specific tier. Digest is tissue chemically hydrolysed into a flavour coating, often sprayed on kibble to make it palatable.
Named by-product meal, such as chicken by-product meal, sits far above generic meat meal in usefulness even though it sounds worse. European formulas frequently lead with named offal and score well on independent reviews; the continental tradition treats lung, heart and liver as food, not filler.
4D meat and what rendering is allowed to take
The genuine safety concern is not "by-product" but "dead, dying, diseased, disabled" animals — the 4D category — entering the render. In the US, rendered feed ingredients are barred from including animals condemned by inspection, and the rendered product must be heat-processed, which is why rendering exists as a pathogen-control step in the first place. What rendering does not do is remove every drug residue, and pentobarbital traces have been documented in some rendered pet food ingredients in past surveys.
In practice the risk concentrates in the cheapest tier of the market, where sourcing is unverifiable and the price signals it. A food at a third of the category average, with "meat and bone meal" high in the list, is making a sourcing bet you cannot check. That is a reason to buy higher, not a reason to fear the word "by-product" in a mid-priced can.
What to check on the bag, in order
- Species named in the first animal ingredient. "Chicken" beats "poultry" beats "meat" every time.
- Whether the food has an AAFCO adequacy statement for the right life stage. Without it, ingredient quality is beside the point.
- The guaranteed analysis: 30%+ protein and a declared taurine level are consistent with a meat-based formula; 26% protein with pea protein high in the list is not.
- Ash, as a rough proxy for bone content. Above 8% dry matter in a canned food suggests a lot of ground bone.
- Whether the manufacturer names the plant or at least the country of manufacture. Recall history is public in most markets and takes two minutes to check.
Where the "by-products are poison" claim comes from
Mostly from marketing written to sell the alternative. The claim is that organs are slaughterhouse waste with no nutritional value, which contradicts every textbook on feline nutrition: obligate carnivores in the wild eat the viscera first, and a mouse is roughly 10% organ by weight. The other half of the claim, that "human-grade" meat is what goes into premium food, is only verifiable when the production facility itself holds a human-food licence — otherwise the phrase has no enforcement behind it.
None of this argues that by-products are always good. A formula can be 60% named by-product meal and still be a poor diet if the fat is rancid, the taurine is not guaranteed, or the batch is inconsistent. The point is that the ingredient class is not the diagnostic. Read the whole label, as set out in reading cat food labels, and judge the formula rather than the word.
How this changes a buying decision
If you are comparing two cans at the same price, take the one that names its species and states taurine. If you are comparing a named-by-product formula at a fair price against a generic meat-meal formula at a suspiciously low one, take the former without hesitation. If a cat has been stable on a food with poultry by-product meal for years, there is no nutritional reason to change it, and every reason to change slowly if you do — switching cat food covers the 7–10 day ramp. Cats with kidney disease should have phosphorus checked before any high-bone product goes in the bowl; the protein side of that calculation is in how much protein cats need.
Frequently asked
Are by-products in cat food dangerous?
Not as a class. AAFCO defines them as clean slaughterhouse tissue other than muscle — liver, heart, kidney, lung, blood, bone — and these carry vitamins and minerals that muscle meat lacks, including the taurine in heart and the vitamin A in liver. The real red flags are unnamed sources such as generic meat meal, and 4D animals entering the render, which is a sourcing problem rather than a by-product problem.
Is chicken meal worse than fresh chicken?
It is more concentrated, not worse. Fresh chicken is about 70% water, so 10 kg of it yields roughly 3 kg of dry matter. Chicken meal is that tissue dried to about 10% moisture with protein above 60%, so a smaller weight supplies more protein. What matters is that the species is named and the formula is complete and balanced.
What should I avoid on an ingredient list?
Generic animal sources: meat meal, meat and bone meal, poultry by-product meal without a species, and animal digest. These are legal but untraceable, and they usually appear in the cheapest tier of the market. Also avoid any food with no AAFCO adequacy statement, because ingredient quality cannot compensate for a formula that is not nutritionally complete.