Ingredient file // Plant protein
Soy Grits
A real protein source, with softer stools
Soy grits are dehulled soybeans, often with the oil removed, ground coarser than soy flour. They add plant protein that dogs digest well, at the cost of slightly wetter, bulkier stools and a methionine gap that meat has to fill.
- What it is
- Dehulled soybeans, usually defatted, milled and screened into granules coarser than soy flour.
- Made from
- Dehulled soybeans, usually after oil extraction
- Main job
- Concentrated plant protein
- Typical amount
- Not published for grits; soy meal trials fed 6 to 17%
- Watch for
- Dogs with a diagnosed soy allergy
- Not the same as
- Corn grits or hominy
Our read // In our catalog
In 1 of every 3068 foods we track
Share of foods that list it
0%
1 of the 3,068 foods with an ingredient list on file, from 1 brand. All dry dog food.
Each square is 1% of the catalog
Where it sits on the label
Median position 3. In the top five of 1 food, so it is usually a main ingredient.
Above the salt
Almost always listed before the salt, so there is more of it than a pinch.
Who leans on it
100%
of the foods that list it are from Purina. 1 brand use it in total.
The story
How oil crushing leftovers became a dog food protein
Soy grits come out of the American soybean crushing industry, which presses beans for oil and sells the protein-rich remainder as feed. In 1923 the Piatt County Soy Bean Co-operative in Monticello, Illinois, opened as the country's first cooperative crusher and the first US plant to pull out the oil with a solvent, benzol. During and after World War II, growers who could barely buy soybean meal formed more cooperatives and built crushers of their own.2,9
Since the mid-1930s, the most widely used soy flour in the world has been made by grinding the defatted flakes left after a solvent strips out the oil, and grits are that flour ground coarse. Output climbed fast: US plants made more than 115,000 tonnes of soy flour and grits by 1943 and over 300,000 tonnes at the 1948 peak, most of it for relief feeding in Europe. Soybean meal for animal feed is a far larger stream.2,8
Purina says that in 1957 it became the first company to apply extrusion to dog food, cooking ingredients into the shaped pieces now called kibble. The extruder's heat was not enough on its own for soy. In a 2013 trial, raw soybeans run through the extruder reached only 78.9% protein digestibility in adult dogs, against 85.1% for defatted soybean meal, and the authors concluded soy works only when heat treated before extrusion.10,11
What it is
How it is made
Soy grits come out of the same crushing plants that make soybean oil. Once the oil is extracted, the defatted flakes are milled and sifted: the finest particles sell as soy flour, the coarser ones as grits.1,2
- 01 // Source Soybeans Whole beans, about 43% protein and 20% fat on a dry basis, arrive at an oilseed plant.
- 02 // Process Dehulled and flaked Hulls, about 8% of the seed, are cracked off. Edible soy flours and grits always start from dehulled beans.
- 03 // Process Oil extracted Solvent percolates through the flakes and carries the oil away, leaving defatted flakes under 1% fat.
- 04 // Process Heated and milled Heat inactivates trypsin inhibitors and urease. The flakes are then ground and sifted by particle size.
- 05 // Output Soy grits Granules of 10 to 80 mesh, coarser than soy flour, which must pass a 100-mesh screen.
What is in it
Composition, dry matter
59
% protein
Protein in defatted soy flour on a dry basis. Grits share that composition, so this is a protein ingredient first, not a starch.
Benefits
What it does for your dog
Each benefit carries the same evidence grade as the claims below.
-
01
Protein the dog actually absorbs
Heat-treated soy reached about 85% protein digestibility in a 6-dog trial, and in a separate 12-dog trial protein digestibility rose as soybean meal replaced chicken protein. Raw soy scored lower.3,11
- Strong
- Some
- Thin
- None
-
02
Lysine to cover a grain gap
Soy protein is rich in lysine, the amino acid corn and wheat run short on, so it rounds out grain-based kibble. It still needs meat or added methionine beside it.2
- Strong
- Some
- Thin
- None
-
03
More fuel for colon bacteria
Soy sugars ferment in the colon. In a 12-dog trial, fecal short-chain fatty acids rose and pH fell as whole soybeans increased, but that trial used whole beans and measured no health effect.12
- Strong
- Some
- Thin
- None
Why it is in the bag
What the manufacturer gets
-
01
Protein at huge scale
Soybean meal is the main protein feed in the world, about two-thirds of all protein feedstuff output, so soy protein supply is deep, steady and cheaper than meat.2
-
02
Protein dogs digest
In a 12-dog trial, protein digestibility rose as soybean meal replaced dried chicken protein, up to 17% of the diet.3
-
03
Lysine to pair with grain
Soy protein is rich in lysine, which corn and wheat run short on, but low in methionine, so it works beside meat or added methionine.2
How much A 24-week trial in 36 hounds fed soybean meal at up to 17% of the diet as fed, with no change in body weight or bloodwork.3
Our read // The claims
What the evidence supports
Strong: controlled studies in dogs agree. Some: small or mixed dog data. Thin: mechanism or lab work only. None: nothing, or the evidence points the other way.
-
Brands say
Soy is a good protein source for dogs
Evidence
- Strong
- Some
- Thin
- None
In a 24-week, 36-dog trial, soybean meal at up to 17% of the diet left bloodwork normal; in a separate 12-dog trial, protein digestibility rose with it. A 6-dog trial found soy diets less digestible than poultry by-product meal, 87% vs 91% dry matter.3,4
-
Owners say
Soy makes dogs gassy with loose stools
Evidence
- Strong
- Some
- Thin
- None
Stool got wetter and bulkier as soybean meal rose in a 12-dog trial. Gas is less certain: a 6-dog trial saw no rise in flatulence below 22.4 g stachyose per kg of diet.3,4
-
Owners say
Soy is a common dog food allergen
Outruns the evidence
Evidence
- Strong
- Some
- Thin
- None
Soy was the trigger in 18 of 297 dogs with proven food reactions, about 6%, far behind beef at 102 and chicken at 45. It is a real allergen, not a common one.5
-
Critics say
Soy phytoestrogens disrupt dogs' hormones
Outruns the evidence
Evidence
- Strong
- Some
- Thin
- None
Soy dog foods carried daidzein at 24 to 615 µg per g dry matter. In a 1-year, 20-dog trial, high-isoflavone diets shifted thyroxine and estradiol responses but changed no health, blood or urine measure.6,7
-
Critics say
Soy is just cheap filler
Outruns the evidence
Evidence
- Strong
- Some
- Thin
- None
Cheap is fair; filler is not. Defatted soy runs about 59% protein on a dry basis, and a 24-week dog trial found soybean meal kept dogs in normal health.1,3
The research
Studies worth knowing
Published research we read for this page, dog studies first.
-
2013 // Feeding trial, 6 diets
Heated soy protein digested well; raw soybeans fell behind11
6 adult dogs and 6 puppies
Found. Each diet swapped 30% of a reference food for a soy product. Adult dogs digested 85.1% of the protein in defatted soybean meal and 85.2% in soybean meal, but only 78.9% in raw soybeans.
What it means. Soy grits are heated, defatted soy, the form that tested well here, so properly cooked grits give a dog usable protein.
-
2023 // Feeding trial, 4 foods
Whole soybeans cut digestibility slightly, and dogs still preferred them12
12 Beagles for digestion, 20 for taste tests
Found. At 30% whole soybeans, protein digestibility slipped from 88.2% to 85.9%. Stool scores did not change, and dogs picked the soy food first in 29 of 40 tests. A state soybean commission paid for the work.
What it means. Whole beans are not grits, but soy did not put dogs off their food, though stool output rose with more of it.
Straight answers
What owners ask
-
Q01
Is it just filler?
NoAt about 59% protein on a dry basis, soy grits do a real protein job. They cost less than meat, which is why brands use them, but cheap and useless are different things.1
-
Q02
Is it the same as soybean meal?
Close cousinBoth are defatted soy. Grits come from dehulled beans and are sized by screen to food grade, so they carry less fiber, about 2.6% against 4.8 to 10.7% for meal, and a little more protein.1,2
-
Q03
Is soy protein as good as meat?
Not aloneSoy runs short on methionine and cystine, so it needs a partner protein. In complete diets where soy replaced up to 30% of the chicken protein, dogs stayed healthy for 24 weeks.2,3
Who uses it
Brands, best sellers and the company it keeps
Top brands, by foods that list it
Usually listed with, share of the foods that list it
- Beef By-Product 100%
- Soy Flour 100%
- High Fructose Corn Syrup 100%
- Water 100%
- Wheat Flour 100%
- Corn Syrup 100%
- Chicken 100%
- Soy Protein Isolate 100%
- Phosphoric Acid 100%
On the shelf
Foods that list it
1 foods in our reviews list it. Here are some of them.
Our read // On the bag
Count the soy, then check the meat
Soy grits are protein, so read them against the meat. One soy line under a named meat is ordinary. Several soy lines (grits, flour, isolate) near the top mean much of the protein figure is plant protein. Skip it only for a dog with a proven soy allergy.
Sources
What we read
Checked October 1, 2026.
- 1 Technology of production of edible flours and protein products from soybeans. Chapter 4
- 2 Soybean meal
- 3 Effect of graded inclusion of dietary soybean meal on nutrient digestibility, health, and metabolic indices of adult dogs
- 4 In vivo measurement of flatulence and nutrient digestibility in dogs fed poultry by-product meal, conventional soybean meal, and low-oligosaccharide low-phytate soybean meal
- 5 Critically appraised topic on adverse food reactions of companion animals (2): common food allergen sources in dogs and cats
- 6 Identification and concentration of soy phytoestrogens in commercial dog foods
- 7 Effects of dietary soy isoflavones on health, steroidogenesis, and thyroid gland function in dogs
- 8 History of Soy Flour, Grits, Flakes, and Cereal-Soy Blends, Part 1
- 9 History of Cooperative Soybean Processing in the United States (1923-2021)
- 10 A History Of Innovation
- 11 Digestibility and metabolizable energy of raw soybeans manufactured with different processing treatments and fed to adult dogs and puppies
- 12 Apparent total tract digestibility and palatability of extruded diets with graded levels of whole soybeans by dogs