Label analysisGrade DListed ingredientsKibble (Extruded)

Hill's

Hill's z/d Low Fat Hydrolyzed Soy Recipe Dry Dog Food | Hill's Prescription Diet

Choosing for your dog
Editor ingredient insight

Hill’s z/d Low Fat Hydrolyzed Soy starts with corn starch, hydrolyzed soy protein, and powdered cellulose, with high protein but very low fat.

It is worth considering for veterinarian-guided low-fat hydrolyzed feeding, not for soy/corn avoidance.

Plant booster present
Illustration of grains and vegetables beside a dog-food bowl
Grain and vegetable illustration

01. NUTRIENT PROFILE

Key nutrients & mineral profile

As-fed basis
Disclosed protein and fat
Protein 27%Fat 7.4%Other 65.6%Other includes moisture, ash and remaining components.
Position within the same processing type

Compare protein, fat and energy density in low, typical and high bands.

Protein positionTypical

This food sits around the typical crude protein range among extruded foods.

Fat positionLower

This food is on the lower side for crude fat among extruded foods.

Calorie densityLower

This food is on the lower side for calorie density among extruded foods. That alone does not make it a weight-management diet; check portion guidance, fat, and fiber together.

Key guaranteed nutrientsAs-fed
Calcium0.8%
Phosphorus0.55%
Crude fiberNot disclosed
Omega-30.6%
Omega-62.07%

Undisclosed values are not treated as zero.

02. INGREDIENT QUALITY & DISCLOSURE

Disclosed ingredients & ingredient grade

The analysis uses the registered ingredients. Complete-panel coverage is not verified, so an unlisted ingredient cannot be assumed absent.

Listed ingredients

Read the listed ingredients below. Complete-panel coverage is not verified here; do not infer that an unlisted ingredient is absent.

Grains and vegetables ingredient illustration
Grain and vegetable illustration
D1.5/6Ingredient gradeConservative
Ingredient #1 · Corn StarchMid
Refined Carb
Ingredient #2 · Hydrolyzed Soy ProteinLowest
Processed Plant Protein
Ingredient #3 · Powdered CelluloseLower
Fiber Filler
Ingredient #1Mid

Corn Starch

Corn Starch is a refined carbohydrate source. It usually reads as a starch and energy source rather than a protein driver. It reads as an mid-tier carb source.

Ingredient #2Lowest

Hydrolyzed Soy Protein

Hydrolyzed Soy Protein is a processed plant-protein booster. It can lift crude protein without the same animal-protein share, so the animal-protein read should stay separate. It reads as an bottom-tier plant protein booster.

Ingredient #3Lower

Powdered Cellulose

Powdered Cellulose reads as a filler-style fiber ingredient. It is harder to count as a stronger quality signal. It reads as an lower-tier carb source.

Available ingredient listIn disclosed order
Corn Starch — Neutral ingredientsHydrolyzed Soy Protein — High-caution ingredientsPowdered Cellulose — Neutral ingredientsDicalcium Phosphate — Neutral ingredientsSoybean Oil — Neutral ingredientsHydrolyzed Chicken Flavor — Support positive ingredientsGround Pecan Shells — Neutral ingredientsCoconut Oil — Neutral ingredientsLactic Acid — Neutral ingredientsPotassium Chloride — Support positive ingredientsFlaxseed — Neutral ingredientsGlyceryl Monostearate — Neutral ingredientsDried Beet Pulp — Support positive ingredientsDried Citrus Pulp — Neutral ingredientsDL-Methionine — Neutral ingredientsFish Oil — Support positive ingredientsCholine Chloride — Support positive ingredientsCalcium Sulfate — Neutral ingredientsPressed Cranberries — Neutral ingredientsvitamins (Vitamin E Supplement, L-Ascorbyl-2-Polyphosphate (source of Vitamin C), Niacin Supplement, Thiamine Mononitrate, Pyridoxine Hydrochloride, Calcium Pantothenate, Riboflavin Supplement, Vitamin A Supplement, Biotin, Vitamin B12 Supplement, Folic Acid, Vitamin D3 Supplement) — Support positive ingredientsCalcium Carbonate — Neutral ingredientsIodized Salt — Neutral ingredientsTaurine — Support positive ingredientsMagnesium Oxide — Support positive ingredientsminerals (Ferrous Sulfate, Zinc Oxide, Copper Sulfate, Manganous Oxide, Calcium Iodate, Sodium Selenite) — Support positive ingredientsL-Tryptophan — Neutral ingredientsMixed Tocopherols for freshness — Neutral ingredientsNatural Flavors — Support positive ingredientsL-Carnitine — Support positive ingredientsBeta-Carotene. — Neutral ingredients
Primary positive ingredientsSupport positive ingredientsAlternative proteinNeutral ingredientsCaution ingredientsHigh-caution ingredients
Protein sourceIngredient guide

Ingredient-label protein analysis

Plant protein · Hydrolyzed Soy Protein (#2)

This reads less like a natural meat-forward daily food and more like a therapeutic diet designed to reduce allergy reactions.

If your dog can tolerate other animal proteins, keeping a plant-hydrolyzed diet as a lifelong default is not usually the first choice. Use it under veterinary diagnosis and prescription to check diet response.

Included support ingredientsNutrient guide
Fish oilSkin and joint support ingredientCranberryUrinary support ingredientTaurineHeart support ingredientL-carnitineHeart and weight support ingredientOmega-3Skin and joint support ingredientOmega-6Skin and coat support ingredientEPA+DHASkin, joint, and heart support ingredientVitamin EAntioxidant and skin support ingredient

03. CHOOSING FOR YOUR DOG

What to consider before feeding

This is a prescription-diet candidate for allergy/skin care. Read purpose fit and veterinary guidance before treating it as a standard star-ranked food.

What works well in this food

  • Omega-3, Omega-6, EPA+DHA, Vitamin E are disclosed, which helps compare skin-barrier and coat-support markers.
  • Crude protein does not drop into a clearly low band.
  • Calorie density is on the lower side.
  • Top ingredients do not show a prominent FDA-investigated non-hereditary DCM ingredient profile.

Check before feeding

  • Refined carbohydrates lose fiber, vitamins, and minerals during processing, and mainly act as starch and energy sources. Because of that, our engine reads ingredient quality more conservatively than it would with whole grains.
  • Processed plant protein sits in the top 3, so the crude-protein number clearly includes protein support beyond meat ingredients.
  • Public data is usable, but not at the highest-trust tier.

When this food fits your dog

Prescription purpose: allergy/skin care.

Consider it first when

  • Public-data-first comparison
  • Baseline shortlist building
  • Conservative first-pass screening

Choose another food first when

  • You want a stronger ingredient-quality story first
  • You need dog-specific fit instead of public-review screening

Plant-protein concentration remains the clearest trade-off here.

04. COMPARE FOODS

allergy/skin care prescription alternatives

Compare allergy/skin care prescription diets first. For therapeutic diets, clinical fit and veterinary direction matter more than a standard score.

05. MANUFACTURING & DISCLOSURE

Manufacturer background & public information

Hill's background

Founded in 1907 in the United States.

Disclosure confidence C1

There is a usable disclosure baseline, but the public record is still fairly thin.

Recall information

This brand has a confirmed recall history. The most recent public recall noted here was the 2019 vitamin D incident.

May 12, 2026

Final word

Interpret this for my dog

The food-first public score is only the starting point. Once your dog’s activity, weight goals, life stage, and health status are applied, the recommendation order and interpretation can change.

Treat this review as an early screen. If the food stays interesting, verify it again with your dog-specific context before acting.