Hill’s Science Diet Adult Dog Food receives the Advisor’s second-lowest tier rating of 2.5 stars.
The Hill’s Science Diet Adult product line lists 17 dry dog foods, each claimed to meet AAFCO nutrient profiles for adult maintenance.
The following is a list of recipes available at the time of this review.
- Science Diet Adult Oral Care
- Science Diet Adult Large Breed
- Science Diet Adult Light (3 stars)
- Science Diet Adult Sensitive Skin
- Science Diet Adult Sensitive Stomach
- Science Diet Adult Healthy Mobility (2 stars)
- Science Diet Adult Light Small Bites (3 stars)
- Science Diet Adult Advanced Fitness Original
- Science Diet Adult Large Breed Light (3 stars)
- Science Diet Adult Advanced Fitness Small Bites
- Science Diet Adult Small and Toy Breed (3 stars)
- Science Diet Adult Small and Toy Breed Light (3 stars)
- Science Diet Adult Healthy Mobility Small Bites (2 stars)
- Science Diet Adult Healthy Mobility Large Breed (2 stars)
- Science Diet Adult Large Breed Lamb Meal and Rice (3 stars)
- Science Diet Adult Advanced Fitness Lamb Meal and Rice (3 stars)
- Science Diet Adult Advanced Fitness Small Bites Lamb Meal & Rice (3 stars)
Science Diet Adult Advanced Fitness Original was selected to represent the other products in the line for this review.
Hill's Science Diet Adult Advanced Fitness Original
Dry Dog Food
Estimated Dry Matter Nutrient Content
Ingredients: Chicken, whole grain wheat, brewers rice, whole grain sorghum, corn gluten meal, whole grain corn, chicken meal, chicken liver flavor, pork fat, dried beet pulp, soybean oil, lactic acid, flaxseed, potassium chloride, iodized salt, choline chloride, calcium carbonate, vitamins (vitamin E supplement, l-ascorbyl-2-polyphosphate (source of vitamin C), niacin supplement, thiamine mononitrate, vitamin A supplement, calcium pantothenate, biotin, vitamin B12 supplement, pyridoxine hydrochloride, riboflavin supplement, folic acid, vitamin D3 supplement), minerals (ferrous sulfate, zinc oxide, copper sulfate, manganous oxide, calcium iodate, sodium selenite), taurine, oat fiber, mixed tocopherols for freshness, phosphoric acid, beta-carotene, natural flavors, dried apples, dried broccoli, dried carrots, dried cranberries, dried peas
Fiber (estimated dry matter content) = 2%
Red items when present indicate controversial ingredients
|Estimated Nutrient Content|
|Dry Matter Basis||25%||16%||51%|
|Calorie Weighted Basis||21%||34%||45%|
The first ingredient in this dog food is chicken. Although it is a quality item, raw chicken contains about 80% water. After cooking, most of that moisture is lost, reducing the meat content to just a fraction of its original weight.
After processing, this item would probably account for a smaller part of the total content of the finished product.
The second ingredient is wheat. Like corn, wheat is an inexpensive and controversial cereal grain of only modest nutritional value to a dog.
For this reason, we do not consider wheat a preferred component in any dog food.
The third ingredient is brewers rice. Brewers rice is a cereal grain by-product consisting of the small fragments left over after milling whole rice. Aside from the caloric energy it contains, this item is of only modest nutritional value to a dog.
The fourth ingredient is sorghum. Sorghum (milo) is a starchy cereal grain with a nutrient profile similar to corn.
Since it is gluten-free and boasts a smoother blood sugar behavior than other grains, sorghum may be considered an acceptable non-meat ingredient.
The fifth ingredient is corn gluten meal. Gluten is the rubbery residue remaining once corn has had most of its starchy carbohydrate washed out of it.
Compared to meat, glutens are inferior grain-based proteins lower in some of the essential amino acids dogs need for life.
This inexpensive plant-based ingredient can significantly boost the total protein reported on the label — a factor that must be considered when judging the actual meat content of this dog food.
The sixth ingredient is corn. Corn is another cereal grain and subject to the same issues as wheat (previously discussed).
The seventh ingredient is chicken meal. Chicken meal is considered a meat concentrate and contains nearly 300% more protein than fresh chicken.
After the chicken liver flavor, we find pork fat, a product from rendering pig meat.
Commonly known as lard, pork fat can add significant flavor to any dog food. And it can be high in linoleic acid, an omega-6 fatty acid essential for life.
Although it may not sound very appetizing, pork fat (in moderate amounts) is actually an acceptable pet food ingredient.
From here, the list goes on to include a number of other items.
But to be realistic, ingredients located this far down the list (other than nutritional supplements) are not likely to affect the overall rating of this product.
With five notable exceptions…
First, soybean oil is red flagged here only due to its rumored (yet unlikely) link to canine food allergies.
However, since soybean oil is high in omega-6 fatty acids and contains no omega-3′s, it’s considered less nutritious than flaxseed oil or a named animal fat.
Next, we find no mention of probiotics, friendly bacteria applied to the surface of the kibble after processing to help with digestion.
In addition, beet pulp is a controversial ingredient, a high fiber by-product of sugar beet processing.
Some denounce beet pulp as an inexpensive filler while others cite its outstanding intestinal health and blood sugar benefits.
We only call your attention here to the controversy and believe the inclusion of beet pulp in reasonable amounts in most dog foods is entirely acceptable.
Next, flaxseed is one of the best plant sources of healthy omega-3 fatty acids. Provided they’ve first been ground into a meal, flax seeds are also rich in soluble fiber.
However, flaxseed contains about 19% protein, a factor that must be considered when judging the actual meat content of this dog food.
And lastly, the minerals listed here do not appear to be chelated. And that can make them more difficult to absorb. Non-chelated minerals are usually associated with lower quality dog foods.
Hill’s Science Diet Adult Dry Dog Food
The Bottom Line
Judging by its ingredients alone, Hill’s Science Diet Adult Dog Food looks like a below average dry product.
But ingredient quality by itself cannot tell the whole story. We still need to estimate the product’s meat content before determining a final rating.
As a group, the brand features an average protein content of 24% and a mean fat level of 14%. Together, these figures suggest a carbohydrate content of 54% for the overall product line.
And a fat-to-protein ratio of about 60%.
Below-average protein. Below-average fat. And above-average carbs when compared to a typical dry dog food.
When you consider the protein-boosting effect of the corn gluten meal, dried peas and flaxseed contained in this recipe as well as the pea protein and soybean meal in other recipes, this looks like the profile of a kibble containing a below average amount of meat.
Hill’s Science Diet Adult Dog Food is a plant-based kibble using a below average amount of named meats and meat meals as its main sources of animal protein, thus earning the brand 2.5 stars.
Please note some products may have been given higher or lower ratings based upon our estimate of their total meat content.
Rice ingredients can sometimes contain arsenic. Until the US FDA establishes safe upper levels for arsenic content, pet owners may wish to limit the total amount of rice fed in a dog's daily diet.
A Final Word
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For a better understanding of how we analyze each product, please read our article, "The Problem with Dog Food Reviews".
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Notes and Updates
12/27/2009 Original review
08/01/2010 Review updated
11/21/2011 Review updated
02/17/2013 Review updated
11/09/2013 Review updated
11/09/2013 Last Update