By-products and “Meat Meal”: What They Actually Are

If you have ever read a comments thread about cat food, you have seen the rule: avoid by-products. It sounds straightforward. The trouble is that the rule treats a wide category as a single thing, and the category contains both organ meat that cats genuinely need and material that is closer to industrial filler.

Treating by-products as automatically bad misses the real issue. By-products are a black box, and the label rarely tells you what is inside. That is the problem worth focusing on.

What “by-product” actually means

In pet food labelling, by-product is a legal term, not a quality judgement. The relevant definitions come from AAFCO, the American body whose ingredient definitions are also used as the working reference in Australia.

“Meat” is restricted to clean flesh from slaughtered mammals, mainly skeletal muscle, plus a few specific cuts like heart and tongue.

“Meat by-products” covers the parts that are not skeletal muscle but are still clean and from a slaughtered animal: lungs, spleen, kidneys, brain, liver, blood, bone, stomach and intestines once emptied. It explicitly excludes hair, horns, teeth and hoofs.

“Meat meal” is a rendered product, meaning the source material has been ground, cooked and dried into a concentrated powder. It excludes blood, hair, hoof, horn, hide trimmings, manure and gut contents.

“Poultry by-product meal” and “chicken by-product meal” are the rendered version of poultry by-products: necks, feet, undeveloped eggs and intestines, excluding feathers.

None of these definitions tells you anything about quality within the category. A poultry by-product meal that is mostly liver and heart, and a poultry by-product meal that is mostly feet and necks, are both legally the same ingredient.

Why this question is different for cats

Most of the by-product debate online comes from the dog food world, and a lot of it does not transfer cleanly. Cats are obligate carnivores, which we have written about in Why Your Cat Cannot Just Eat Anything. They evolved on whole prey, which means they evolved on organs.

Liver is the densest natural source of vitamin A and several B vitamins. Heart is the richest natural source of taurine, the amino acid cats cannot make in adequate amounts themselves, the absence of which causes dilated cardiomyopathy. Kidneys carry iron and zinc. A wild cat eating a mouse eats all of this alongside the muscle, which is why a diet of pure skeletal muscle, the part humans call “meat,” is actually nutritionally incomplete for a cat.

So a “by-product” that is liver, heart and kidney is not a downgrade from muscle meat. For a cat, it is closer to a return to what the species is built for. The reason commercial cat food supplements taurine is partly to cover formulations that use too little of those organs and rely on muscle meat plus added taurine instead.

This is the part the lazy framing misses. The problem with by-products is not that organ meat ends up in cat food. The problem is that the word covers organ meat and also covers feet and necks, and the label does not separate them.

The rendering process

Most by-products in dry food are not used fresh. They are rendered, which is the process we describe in How Cat Food Is Made: the raw material is ground, cooked at high temperature to kill pathogens and drive off water, separated from fat, and dried into a concentrated meal that ships and stores well.

Rendering itself is unremarkable. It is how almost all dry pet food protein has been processed for decades, the same general process used in livestock feed and some human food applications. What rendering does do is mask the original source. By the time a poultry meal is a dry powder, you cannot tell from looking at it whether it started as chicken liver or chicken feet.

That places all the weight on the label. And the label does not tell you.

The Australian labelling gap

In Australia, the voluntary pet food standard AS 5812 sets out reasonable expectations for ingredient declarations, but two things matter for this question.

The first is that the standard is voluntary, which we have covered in our guide on whether cat food is regulated in Australia. A manufacturer is not obliged to follow it.

The second is that even brands that do follow it are permitted to use collective terms. A label can list “meat meal” without naming the species. It can list “poultry by-products” without specifying whether that is liver and heart or necks and feet. Multiple species can be combined under a single line.

This is the labelling pattern KibbleGuide flags on a product page as collective labelling, because the term covers a range so wide it stops being useful for the reader. “Chicken meal” tells you something. “Meat meal” tells you almost nothing.

What to actually look for

A few practical signals from a label, in order of how much they tell you.

Named species is the first one. “Chicken by-product meal” is more transparent than “poultry by-product meal,” which is more transparent than “meat meal.” Naming the species does not guarantee high-value parts, but the unwillingness to name the species usually means the manufacturer is keeping options open across multiple suppliers, which means you have less idea what is in the bag from one batch to the next.

Named first ingredient is the second. A fresh, named meat or a named meal as the first ingredient is a stronger position than a vague meat term, regardless of what comes after.

Brand willingness to disclose is the third. A brand that publishes which organs and cuts make up its named meals on request, or in its product information, is doing something the law does not require. That is worth knowing.

The thing not to do is to read “by-product” on a label and reach for the next bag automatically. Some by-products are exactly what a cat needs. The right question is whether the label is precise enough for you to tell.

Related reading

• Why Your Cat Cannot Just Eat Anything Why obligate carnivory makes organ meat valuable rather than disposable.
• How Cat Food Is Made The rendering, extrusion, and freeze-drying processes behind each format.
• The Label Guide How to read an Australian cat food label and what manufacturers are not required to disclose.

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