Is IAMS or Purina one better for cats

By Isabella Storyclaire

last updated September 16, 2024

Contributions sourced from

Iams vs. Purina One

In this comparison article for Iams vs Purina One, we'll highlight the key differences between these two pet food brands. To properly compare Iams and Purina One, we'll use up-to-date nutritional and price information.

There are many factors to consider when choosing the best pet food brand for your pet. Factors such as ingredient quality, guaranteed analysis, product safety, brand history, and cost are among the most important factors to consider.

Throughout this Purina One vs Iams comparison, we've utilized average data to make general comparisons. If you'd like to see individual product reviews, visit our Iams Review Page or Purina One Review Page.

Guaranteed Analysis: Purina One vs. Iams

According to AAFCO, all pet food labels must provide a guaranteed analysis of nutrient content. The analysis must provide guaranteed minimum percentages of crude protein and crude fat, and maximum percentages of crude fiber and moisture.

All percentages used in this comparison are averages reported on a dry matter basis.

Iams Dog Food vs. Purina One Dog Food

Dry Dog Food	Iams	Purina One
Crude Protein	27.6%	32.0%
Crude Fat	14.9%	17.4%
Crude Fiber	5.2%	4.1%

Wet/Canned Dog Food	Iams	Purina One
Crude Protein	40.9%	45.6%
Crude Fat	23.4%	26.0%
Crude Fiber	5.4%	7.1%

Crude Protein Comparison For Dog Food

Dogs require twenty-two amino acids to sustain life. Twelve of these amino acids are synthesized naturally, the remaining ten are consumed. Protein is the nutrient which provides some or all of these ten essential amino acids.

The table shows that Iams provides far less protein than Purina One. The difference in protein content is roughly 4.37%. In addition, Purina One wet dog foods also provide more protein than Iams wet foods.

Crude Fat Comparison For Dog Food

Like protein, fats are an essential part of a dog's body. Fats are needed for the proper development and function of the canine body.

If you look at the average percentages of crude fat, you'll notice that Purina One typically guarantees 2.51% more fat. This is a fairly small difference between Purina One and Iams, but still worth mentioning. In addition, Purina One wet dog foods also provide more fat than Iams wet foods.

As you can see, Purina One and Iams guarantee a similar amount of crude fiber. With regards to wet dog food, Purina One and Iams also provide roughly the same amount of crude fiber.

Iams Cat Food vs. Purina One Cat Food

Dry Cat Food	Iams	Purina One
Crude Protein	35.7%	40.4%
Crude Fat	15.9%	15.2%
Crude Fiber	4.6%	3.7%

Wet/Canned Cat Food	Iams	Purina One
Crude Protein	46.7%	52.9%
Crude Fat	21.8%	16.8%
Crude Fiber	4.9%	7.6%

Crude Protein Comparison For Cat Food

Cats require twenty-two amino acids to sustain life. Eleven of these amino acids are synthesized naturally, the remaining eleven are consumed. Protein is the nutrient which provides some or all of these eleven essential amino acids.

Our analysis shows that Purina One guarantees 4.70% more protein than Iams dry cat food recipes. In addition, Purina One wet cat foods also provide more protein than Iams wet foods.

Crude Fat Comparison For Cat Food

There are many ways in which dietary fat contributes to the overall health of our feline friends. Here is a short list of benefits provided by fats (not exhaustive):

Help transport nutrients across cell membranes
Fats produce metabolites, which help control inflammation
Maintain healthy blood pressure
Slow the growth of yeast infections
Fats improve the taste/texture of food.

Purina One and Iams both provide roughly the same amount of crude fat. For wet cat foods, Iams provides more fat (about 4.95% more).

There is a relatively insignificant difference between the crude fiber content of the two brands. For wet cat foods, Purina One typically provides a little more fiber (about 2.70% more).

Iams Pet Food Ingredients vs. Purina One Pet Food Ingredients

Iams and Purina One both use the following controversial ingredients in many of their products:

Liver

Liver is a controversial ingredient because the source animal is not specified. Anonymous animal ingredients are typically very low quality and may contain almost any animal, including dogs and cats!

Pea Protein

Pea protein is produced by removing the starchy parts of peas. Pea protein is considered controversial because it provides a substantial plant based protein boost. This boost is undesirable because plant based protein is typically lower in biological value when compared to meat based proteins.

Brewers Rice

Brewer's rice is the small fragments of rice kernel that are separated from the larger kernels of milled rice. The fragments do not contain the same nutrition profile of the whole kernel and therefore brewer's rice is a lower quality grain. Brewer's rice is typically regarded as an inexpensive and low quality filler.

Wheat Gluten

Wheat gluten is the main protein of wheat. Although wheat gluten is mostly protein, wheat gluten is considered controversial because it significantly boosts the protein content of the product. This is undesirable because plant based protein does not provide the same amino acid profile as meat based protein.

Caramel Color

Caramel color is a concentrated form of caramel, a natural food colorant. Caramel color has been linked to cancer in laboratory animals. Since our pets do not care about food color, caramel color is an unnecessary addition with possible health risks.

Corn Gluten Meal

Corn gluten meal is a by-product from the production of various corn products (corn starch, corn syrup, etc). It's very high in protein (nearly 60% protein) and therefore can significant boost the protein content of the product. Because plant based proteins such as corn gluten meal are inferior to meat based proteins (lack many essential amino acids), they are not suitable substitutes.

Meat By-Products

By-products are defined by AAFCO as the "non-rendered, clean parts, other than meat, derived from slaughtered mammals." Thus, meat by-products contain nearly all parts of the animal which are typically not consumed by humans. These parts include the liver, lung, spleen, kidney, stomach, blood, intestine, bone, etc.

This ingredient is marked controversial because the meat source is not identified. Anonymous ingredients such as meat by-products are typically very low quality additions. The most unpleasing property of this ingredient is that the animal source can contain any mammal, even dogs & cats.

Powdered Cellulose

Powdered cellulose is produced from minuscule pieces of wood pulp and plant fibers. Other than its fiber content, powdered cellulose lacks any nutritional contribution.

Chicken By-Product Meal

Chicken by-product meal is produced by cooking chicken by-products using a process called rendering. By-products are defined by AAFCO as the "non-rendered, clean parts, other than meat, derived from slaughtered mammals." Thus, chicken by-products contain nearly all parts of chickens which are typically not consumed by humans. These parts include the liver, lung, spleen, kidney, stomach, blood, intestine, bone, etc.

Like other meat by-products, chicken by-products are considered controversial, mainly because they are inexpensive ingredients which consumers have equated with slaughterhouse waste. However, manufactures and many experts claim that animal by-products are unjustly criticized. Proponents state that "named" by-products, such as chicken by-products, supply many important nutrients required by pets.

Animal Fat (Preserved With Mixed Tocopherols)

Animal fat is a by-product of tissue rendering. The source animal is not specific and therefore we cannot be certain that the source does not include diseased animals or even euthanized dogs and cats.

Here are some of the controversial ingredients used only by Iams.

Caramel

Caramel is a widely used natural food colorant. The concentrated form of caramel is typically listed as caramel color and has been linked to cancer in laboratory animals. Since our pets do not care about food color, caramel is an unnecessary addition with possible health risks.

Beet Pulp

Beet pulp is the by-product which remains once sugar has been extracted from sugar beets. The primary contribution of beet pulp is dietary fiber.

We'd also like to note that beet pulp is fairly controversial in pet food. Proponents claim that beet pulp can promote intestinal health and regulate blood sugar. However, opponents claim that beet pulp is an inexpensive filler.

Corn Meal

Corn meal is another name for ground corn. Corn is a cereal grain which provides a modest amount of vitamins, minerals, and plant based protein. It also happens to be one of the most controversial ingredients in pet food.

Proponents of corn claim that corn is highly digestible and an excellent source of protein, energy, vitamins, minerals, and essential fatty acids.

Opponents however believe that positive claims in regards to corn are either half-truths or completely false, we'll discuss a few of the opposing arguments.

In regards to digestibility, the claims of "highly digestible" are only true if corn is processed into a meal or flour and subsequently cooked. In regards to the protein contribution, we must note that corn is a plant based protein which does not contain all of the necessary amino acids required by pets to sustain life. Therefore substituting corn for meat is an unsuitable substitution and actually degrades the overall protein quality of the product.

Finally, we'll discuss the claims about vitamins and minerals in corn. Although corn does provide many vitamins and minerals, it not necessarily an exceptional ingredient in this regards. There are many other ingredients which are more complete and biologically appropriate. Therefore the usage of corn as the primary ingredient in pet food should certainly warrant further questioning.

Canola Oil

Canola oil is a plant-derived oil from the seeds of canola plants. Although fat is an essential component of any diet, canola oil is controversial in pet food. Proponents claim that canola oil provides a better fat profile in comparison to other plant based oils. However, opponents claim that canola oil is typically produced with genetically modified rapeseed and that rapeseed oil has multiple adverse health affects.

Corn Grits

Corn grits are made from ground corn. Corn is a cereal grain which provides a modest amount of vitamins, minerals, and plant based protein. It also happens to be one of the most controversial ingredients in pet food.

Proponents of corn claim that corn is highly digestible and an excellent source of protein, energy, vitamins, minerals, and essential fatty acids.

Opponents however believe that positive claims in regards to corn are either half-truths or completely false, we'll discuss a few of the opposing arguments.

Iron Oxide

Iron oxide is an FDA approved natural food coloring agent. It's commonly found in rusting metal and provides a reddish-brown color.

We believe food colorants are unnecessary ingredients in pet food. Other than potential harm, food colorants do not provide any nutritional value. These type of ingredients are used only to make the food look appealing to humans.

Fish Digest

Fish digest is the result of undecomposed fish tissue after hydrolysis, a chemical reaction. It is typically used as flavoring to improve taste. Fish digest is considered by many as an undesirable low-quality ingredient.

Ground Corn

Ground corn is a cereal grain which provides a modest amount of vitamins, minerals, and plant based protein. It also happens to be one of the most controversial ingredients in pet food.

Proponents of corn claim that corn is highly digestible and an excellent source of protein, energy, vitamins, minerals, and essential fatty acids.

Opponents however believe that positive claims in regards to corn are either half-truths or completely false, we'll discuss a few of the opposing arguments.

Vegetable Oil

Specific vegetable oils are typically positive ingredients; however, this ingredient does not specify which vegetable(s) were used to produce the oil.

Without this information, it is impossible for us to make any specific statements. With any fat source, it is important to know the omega-3 to omega-6 fatty acid ratio, a property which cannot be determined with this ingredient. Thus, we have marked vegetable oil as a controversial ingredient.

Feeding Oatmeal

According to AAFCO, feeding oatmeal "is obtained in the manufacture of rolled oat groats or rolled oats". It contains "broken oat groats, oat groat chips, and floury portions of the oat groats." In other words, feeding oatmeal is an inexpensive by-products of rolled oat processing.

Poultry Giblets

Poultry giblets includes the heart, liver, gizzards, and other internal organs of poultry. Organs are nutritiously dense ingredients which provide high quality protein and fat. However, this particular ingredient is considered an anonymous meat ingredient because the type of poultry is not specified. In order words, "named" giblets such as chicken giblets or turkey giblets are preferred over poultry giblets.

Chicken By-Products

By-products are defined by AAFCO as the "non-rendered, clean parts, other than meat, derived from slaughtered mammals." Thus, chicken by-products contain nearly all parts of the chicken which are typically not consumed by humans. These parts include the liver, lung, spleen, kidney, stomach, blood, intestine, bone, etc.

Dried Tomato Pomace

Dried tomato pomace is a by-product of tomato manufacturing. It's considered a controversial ingredient because many people believe it is an inexpensive low quality filler. However, tomato pomace provides a notable amount of dietary fiber, B vitamins, Lycopene, and vitamin A. Although it is a very inexpensive ingredient, it is not nutritionally empty.

Dried Meat By-Products

By-products are defined by AAFCO as the "non-rendered, clean parts, other than meat, derived from slaughtered mammals." Thus, dried meat by-products contain nearly all parts of the animal which are typically not consumed by humans. These parts include the liver, lung, spleen, kidney, stomach, blood, intestine, bone, etc.

This ingredient is marked controversial because the meat source is not identified. Anonymous ingredients such as dried meat by-products are typically very low quality additions. The most unpleasing property of this ingredient is that the animal source can contain any mammal, even dogs & cats.

Ground Whole Grain Corn

Ground whole grain corn contains the entire corn kernel (the germ, bran, and endosperm). Corn is a cereal grain which provides a modest amount of vitamins, minerals, and plant based protein. It also happens to be one of the most controversial ingredients in pet food.

Proponents of corn claim that corn is highly digestible and an excellent source of protein, energy, vitamins, minerals, and essential fatty acids.

Opponents however believe that positive claims in regards to corn are either half-truths or completely false, we'll discuss a few of the opposing arguments.

Poultry By-Product Meal

Poultry by-product meal is a controversial ingredient because the source animal is not specified. Anonymous ingredients such as poultry by-product meal are typically low-quality ingredients in comparison to named protein by-product meals (e.g. chicken by-product meal, turkey by-product meal, duck by-product meal).

Poultry Fat (Preserved With Mixed Tocopherols)

Poultry fat is a by-product of poultry tissue rendering. Poultry fat is a controversial ingredient because the specific protein is not specified. Such ingredients are typically low-quality in comparison to named poultry fats (e.g. chicken fat, turkey fat).

Here are some of the controversial ingredients used only by Purina One.

Canola Meal

Canola meal is a high protein by-product of canola oil production. This ingredient is marked controversial because it may be derived from genetically modified rapeseed, which is associated with multiple adverse health affects.

Animal Digest

Animal digest is the result of undecomposed animal tissue after hydrolysis, a chemical reaction. It is typically used as flavoring to improve taste. Animal digest is considered by many as an undesirable low-quality ingredient. What's more, the source animal is not specified and therefore animal digest can contain almost any animal, including dogs and cats!

Soybean Flour

Soybean flour contains more than 50% protein. Therefore, soybean can significantly boost the protein content of the product. The inclusion of non-meat protein typically degrades the overall quality of protein in the recipe. This degradation is due to the inferior amino acid profile of plant based proteins.

Soybean Hulls

Soybean hulls are a by-product of soybean oil and meal processing. They are typically regarded as low quality and inexpensive fillers which lack any significant nutritional value.

Corn Germ Meal

Corn germ meal is a high protein by-product of the oil extraction process from corn (maize). It's considered controversial because plant based protein does not contain all of the necessary amino acids required by pets to sustain life. Therefore substituting corn germ meal protein for meat based protein is an unsuitable substitution and actually degrades the overall protein quality of the product.

Whole Grain Corn

Whole grain corn is the entire corn kernel (the germ, bran, and endosperm). Corn is a cereal grain which provides a modest amount of vitamins, minerals, and plant based protein. It also happens to be one of the most controversial ingredients in pet food.

Proponents of corn claim that corn is highly digestible and an excellent source of protein, energy, vitamins, minerals, and essential fatty acids.

Opponents however believe that positive claims in regards to corn are either half-truths or completely false, we'll discuss a few of the opposing arguments.

Whole Grain Wheat

Whole grain wheat contains the entire grain of wheat (the germ, bran, and endosperm). Wheat is the second most-produced cereal grain in the world (corn is the first). Although wheat is a controversial ingredient, it is not necessarily undesirable because it provides dietary fiber and many other nutrients. However, wheat contains a notable amount of plant based protein, which is inferior to meat based protein and therefore an undesirable substitution.

Wheat is also one of the most common ingredients to cause food allergies or intolerance. However, grains such as wheat are typically low offenders in comparison to certain protein sources (such as beef).

Ground Yellow Corn

Ground yellow corn is a cereal grain which provides a modest amount of vitamins, minerals, and plant based protein. It also happens to be one of the most controversial ingredients in pet food.

Proponents of corn claim that corn is highly digestible and an excellent source of protein, energy, vitamins, minerals, and essential fatty acids.

Opponents however believe that positive claims in regards to corn are either half-truths or completely false, we'll discuss a few of the opposing arguments.

Poultry By-Products

By-products are defined by AAFCO as the "non-rendered, clean parts, other than meat, derived from slaughtered mammals." Thus, poultry by-products contain nearly all parts of poultry which are typically not consumed by humans. These parts include the liver, lung, spleen, kidney, stomach, blood, intestine, bone, etc.

Like other meat by-products, poultry by-products are considered controversial, mainly because they are inexpensive ingredients which consumers have equated with slaughterhouse waste. However, manufactures and many experts claim that animal by-products are unjustly criticized. Proponents state that by-products, such as poultry by-products, supply many important nutrients required by pets. Finally, we must also note that this ingredient is considered an anonymous meat ingredient because the specific type of poultry is not specified. By-products which are "named", such as chicken by-products are typically higher in quality when compared to the more general poultry by-products.

Soybean Protein Isolate

Soy protein isolate is a highly refined/purified form of soy bean protein. Roughly 90% of soy protein isolate is protein. The inclusion of non-meat protein typically degrades the overall quality of protein in the recipe. This degradation is due to the inferior amino acid profile of plant based proteins.

Soybean Protein Concentrate

Soybean protein concentrate is produced by removing the water soluble carbohydrates from soybeans. The inclusion of non-meat protein typically degrades the overall quality of protein in the recipe. This degradation is due to the inferior amino acid profile of plant based proteins.

We believe that certain pet food ingredients are linked to adverse health affects; these ingredients are classified as harmful.

Iams and Purina One both use the following harmful ingredients in many of their products:

Added Color

The ingredient "added color" is ambiguous and may include various artificial dyes. Most artificial dyes have been linked to various chronic diseases.

Menadione Sodium Bisulfite Complex

Menadione sodium bisulfite complex is a synthetic version of vitamin K that has been linked to many health concerns. Research has suggested possible toxic reactions in liver cells and red blood cells among other serious problems. In fact, one large chemical supplier warns, "The substance is toxic to kidneys, lungs, liver, mucous membranes. Repeated or prolonged exposure to the substance can produce target organs damage."

Here are some of the harmful ingredients used only by Iams.

Blue 2

Blue 2 is an artificial dye which can increase the likelihood of tumors according to the Center for Science in the Public Interest. Like other dyes, blue 2 does not provide any nutritional value.

Red 40

Red 40 is the most widely used artificial dye in consumer goods. Studies have shown that red 40 may accelerate the appearance of immune-system tumors in mice, cause allergy-like reactions and trigger hyperactivity in children.

Yellow 5

Yellow 5 is an artificial dye which may be contaminated with several cancer-causing chemicals. Like other dyes, yellow 5 does not provide any nutritional value.

Yellow 6

Yellow 6 is an artificial food dye which may be contaminated with cancer-causing chemicals. According to the Center For Science In The Public Interest, yellow 6 can cause adrenal tumors in animals.

Here are some of the harmful ingredients used only by Purina One.

Red 3

Red 3 is an artificial dye which the FDA has confirmed can cause cancer in laboratory animals.

Corn Oil

Corn oil is extracted from the germ of corn kernels. It contains an omega-6 to omega-3 fatty acid ratio of 49:1. Corn oil's unfavorable omega-6 to omega-3 fatty acid ratio makes it an undesirable ingredient. Consumption of such ingredients can lead to an array of health problems in both animals and humans.

Product Safety: Recall History of Iams & Purina One?

Iams has been recalled 2 times.

Aug. 14, 2013: Salmonella
July 30, 2010: Salmonella

Purina One has been recalled once.

Aug. 30, 2013: Salmonella

Price Comparison: Which Brand Is More Expensive?

Dry Dog Food	Iams	Purina One
Per Pound	$1.52	$2.24
Per Calorie	$0.0009	$0.0013

Dry Cat Food	Iams	Purina One
Per Pound	$2.03	$2.05
Per Calorie	$0.0012	$0.0012

Wet Dog Food	Iams	Purina One
Per Pound	$1.90	$2.17
Per Calorie	$0.0038	$0.0043

Wet Cat Food	Iams	Purina One
Per Pound	$6.97	$6.24
Per Calorie	$0.0151	$0.0142

The average cost-per-lb is heavily influenced by the varying amounts of moisture present in each brand's food products (wet vs. dry food, dry vs. freeze-dried food, etc). However, the average cost-per-kcal eliminates the influence of moisture. Therefore, the average cost-per-kcal is the better metric to consider.

If you'd like to calculate the average cost-per-day or cost-pet-year of feeding Iams or Purina One, input your pet's weight into our cost analyzer widget.

Averages price data can identify whether or not there exists a significant price difference between two brands. However, the actual price that you'll pay for Iams or Purina One will depend on your shopping habits.

Pet owners who use our price comparison feature typically save more than 25% off retail prices for Iams and Purina One. In addition, we currently have some great coupons for our readers.

Disclosure: PawDiet has an affiliate relationship with stores featured (or linked-to) in this article. We are compensated for referring customers. Thank you for shopping with our retail partners!

Where To Buy Iams Pet Foods

You can purchase Iams pet foods from the following stores:

33 Recipes In-Stock Today

15 Recipes In-Stock Today

24 Recipes In-Stock Today

Where To Buy Purina One Pet Foods

You can purchase Purina One pet food products from these retailers:

47 Recipes In-Stock Today

23 Recipes In-Stock Today

47 Recipes In-Stock Today

Type Of Pet Foods Available

Product	Iams	Purina One
Dry Dog Food	24 Recipes	19 Recipes
Wet Dog Food	8 Recipes	17 Recipes
Dog Treats	None	4 Treats
Dry Cat Food	13 Recipes	11 Recipes
Wet Cat Food	13 Recipes	16 Recipes
Cat Treats	2 Treats	None