z/d Low Fat Hydrolyzed Soy Recipe Dry Dog Food
Verified Jun 10, 2026
This is a veterinary therapeutic dry food for adult dogs that need a low‑fat, hydrolyzed-protein diet due to food sensitivities or certain digestive issues. It uses hydrolyzed soy as the main protein source with corn starch as the primary carbohydrate, keeping overall fat quite low while still meeting adult maintenance needs. Added omega fatty acids, fiber sources, and antioxidants are included to support skin, coat, and digestive health.
Nutritionally, this is a very well-designed prescription diet for adult dogs who require both a novel, hydrolyzed protein and reduced fat intake. The protein, fat, and fiber levels are appropriate for a low‑fat therapeutic food, and the hydrolyzed soy and hydrolyzed chicken flavor are intended to reduce the chance of triggering food reactions. AAFCO feeding trials and the inclusion of omega-3s, omega-6s, and carnitine add confidence in both digestibility and overall nutritional adequacy for its intended use.
The KibbleLab Score (1–10) is assessed from publicly available product data. Our evaluation is science-based, not marketing-based.
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At a Glance
KibbleLab Review
Strengths
- Hydrolyzed soy protein and hydrolyzed chicken flavor are specifically processed to reduce the likelihood of food-allergic reactions while still providing complete protein.
- Low fat content (around 7.4% on a dry matter basis) is appropriate for dogs that need dietary fat restriction under veterinary guidance.
- Formulated and proven through AAFCO feeding trials to provide complete and balanced nutrition for adult maintenance, which gives good evidence of digestibility and nutrient availability.
- Includes omega-3 and omega-6 fatty acids, added antioxidants (vitamin C, vitamin E, beta-carotene), and L-carnitine, which can support skin, coat, and metabolic health in dogs on a therapeutic diet.
Considerations
- Relies on soy as the primary protein source; while hydrolyzed, this may not be ideal for dogs that must avoid soy entirely for medical reasons as determined by a veterinarian.
- Contains chicken-derived flavor, so it may not be suitable if a dog must strictly avoid all chicken ingredients despite the hydrolysis.
- This formula is specifically designed for adult dogs and is not appropriate for growing puppies or pregnant/lactating females unless a veterinarian directs otherwise.
- Because it is a therapeutic, low‑fat diet, it should be used under veterinary supervision to be sure it fits your dog’s specific medical and nutritional needs.
Full Ingredient List
Ingredients and analysis reflect manufacturer data at the time of our last update and can change without notice. Always check the actual product packaging before feeding.
Ingredient filtering helps identify compatible options but is not a substitute for a veterinary elimination diet.
Top 5 Ingredients Explained
01
Corn Starch
Corn starch is a concentrated carbohydrate used in pet foods primarily as a thickener, binder and texture enhancer for kibbles, treats and canned gravies. It supplies digestible calories with minimal protein or micronutrients, so while generally safe for most dogs and cats it can contribute to excess calories and blood‑sugar increases in overweight or diabetic pets and may be a concern for animals with grain sensitivities.
02
Hydrolyzed Soy Protein
Hydrolyzed soy protein is a processed plant protein broken into small peptides and amino acids and is used in pet foods as a digestible protein source and flavor enhancer, often in hypoallergenic or limited‑ingredient formulations. It can improve digestibility and may reduce allergic reactions for some animals, but it may still trigger soy‑sensitive pets, does not supply certain nutrients cats need from animal proteins (e.g., taurine), and formulations should be evaluated for added sodium or flavoring compounds.
03
Cellulose Powder
Cellulose powder is an insoluble, plant-derived fiber commonly used in pet foods as a bulking agent, binder and calorie-diluting texturizer to help control weight and improve stool formation; it is not digestible by dogs or cats and contributes negligible energy or vitamins. While it can aid stool consistency and manufacturing performance, cellulose is non‑fermentable so offers little prebiotic benefit, and high inclusions can reduce palatability or displace nutrients—formulations, especially for cats with lower fiber tolerance, should be balanced accordingly.
04
Dicalcium Phosphate
Dicalcium phosphate is an inorganic mineral supplement commonly added to dog and cat foods to supply concentrated, bioavailable calcium and phosphorus for healthy bone and teeth formation as well as general metabolic processes. It must be used in balanced amounts (typical Ca:P targets ≈1:1–1.4:1) because improper ratios or excess phosphorus can contribute to skeletal problems in growing animals and worsen conditions like chronic kidney disease, so formulation and dosing should be carefully controlled.
05
Soybean Oil
Soybean oil is used in pet foods as a concentrated fat source and palatability enhancer, providing energy and omega‑6 fatty acids (primarily linoleic acid) that support skin and coat condition. Because it is calorie‑dense and higher in omega‑6 than omega‑3, formulators balance it with omega‑3 sources to avoid an inflammatory imbalance; highly refined soybean oil is unlikely to trigger soy protein allergies but can oxidize and should be stabilized and stored properly, and it does not supply the arachidonic acid cats require from animal fats.
Nutritional Breakdown
How to read As Fed versus Dry Matter
As fed shows the numbers straight off the label, water included. Dry matter removes the water so you can compare a wet food and a dry food fairly.What is calorie density
How many calories the food packs per unit. Denser foods mean smaller portions for the same calories.Product Details & Brand
Product Specs
AAFCO Nutritional Adequacy
What is AAFCO
Association of American Feed Control Officials. It sets the nutritional
adequacy standards US pet foods are measured against.
What is AAFCO
Association of American Feed Control Officials. It sets the nutritional adequacy standards US pet foods are measured against.Brand
Hill's Prescription Diet offers clinically formulated therapeutic nutrition designed to help manage specific health conditions in pets such as kidney disease, urinary issues, skin sensitivities, digestive problems, and weight management. Sold primarily through veterinarians, it's backed by research from Hill's Pet Nutrition Center and veterinary nutritionists.
Visit Hill's Prescription DietWSAVA publishes criteria for evaluating a manufacturer (qualified nutritionists, feeding trials, published research); it does not certify or endorse brands.
Manufacturer
Hill's Pet Nutrition maintains strict quality and safety standards in all of its manufacturing sites, with adherence to rigorous ingredient testing and safety validation procedures. Facilities follow current Good Manufacturing Practices (cGMPs) and are regularly audited for quality, safety, and consistency. All products meet or exceed AAFCO and FDA regulatory standards for pet food.
Manufacturing details are compiled from public sources and not independently verified; they may not reflect contract manufacturing or co-packing.
Recall History
Hill's Prescription Diet z/d Low Fat Hydrolyzed Soy Recipe Dry Dog Food has no recalls since 2014.
Source: FDA Pet Food Recall Database · Monitored daily
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Frequently Asked Questions
Has Hill's Prescription Diet ever been recalled?
We have no recalls on record for Hill's Prescription Diet. We monitor the FDA Pet Food Recall Database daily.
How does KibbleLab rate foods?
Our scores are based on ingredient composition, nutritional profile, AAFCO compliance, and health considerations. We don't penalize by-products, grains, or synthetic preservatives. Brands cannot pay for higher scores.
Is KibbleLab a substitute for veterinary advice?
No. KibbleLab provides data-driven food analysis, not medical advice. Always consult your veterinarian before making dietary changes, especially for pets with health conditions.
KibbleLab provides informational content only. This is not veterinary advice. Always consult a qualified veterinarian before changing your pet's diet.
KibbleLab may earn affiliate commissions through product links. No one can pay for a higher score, or to change what we recommend for your pet.
Product data sourced from manufacturer websites, AAFCO statements, and FDA recall database. Last verified dates reflect our most recent data check.
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