The scores
Hill’s Prescription Diet w/d: B (76/100)
Hill’s Science Diet: C (61/100)
A 15-point gap. w/d’s more diverse grain base and lack of cheap protein fillers earn it a full grade tier above Science Diet.
How the ingredients compare
w/d: Whole Grain Wheat, Powdered Cellulose, Chicken Meal, Whole Grain Corn, Corn Gluten Meal
Science Diet: Chicken, Cracked Pearled Barley, Brown Rice, Brewers Rice, Whole Grain Wheat
Science Diet leads with chicken; w/d leads with wheat and cellulose. But w/d adds barley and oats further down for a four-grain fiber profile designed for glycemic control, while Science Diet fills later positions with soybean meal and multiple palatability flavors.
Where Hill’s Prescription Diet w/d pulls ahead
The four-grain base (wheat, corn, barley, oats) provides diverse soluble and insoluble fibers for blood sugar management. Cracked pearled barley is particularly effective for glycemic control. L-Carnitine supports fat metabolism. Potassium citrate manages urinary pH. Flaxseed adds omega-3s. Taurine supports heart health. w/d avoids soybean meal entirely. The multi-condition engineering is genuinely thoughtful — each ingredient serves at least one of the four therapeutic goals. Shop on Amazon →
Where Hill’s Science Diet holds its own
Whole chicken at position one beats chicken meal at three. Science Diet avoids powdered cellulose. FOS prebiotics in Science Diet support gut health, which w/d — despite targeting digestive health — lacks. Science Diet costs less and doesn’t require a prescription. For healthy dogs without diabetes, weight issues, or urinary problems, Science Diet provides a more protein-forward formula. Shop on Amazon →
The bottom line
Hill’s Prescription Diet w/d (B/76) wins on ingredient quality over Science Diet (C/61). The therapeutic fiber profile and multi-condition management are real. If your vet prescribed w/d for diabetes, weight with complications, or multi-condition management, it’s a well-designed choice. For healthy dogs wanting a Science Diet upgrade, Blue Buffalo (B/78) or Kirkland Signature (B/78) offer better value.