The scores
4Health Adult Salmon & Potato: B (78/100) — Salmon, Salmon Meal, Potatoes, Peas, Potato Starch.
Purina Pro Plan Savor Shredded Blend: C (58/100) — Chicken, Rice, Whole Grain Wheat, Poultry By-Product Meal, Whole Grain Corn.
How the ingredients compare
Here are the first five ingredients on each label — the part of the panel that drives most of the score under our published rubric:
4Health: Salmon, Salmon Meal, Potatoes, Peas, Potato Starch
Purina Pro Plan: Chicken, Rice, Whole Grain Wheat, Poultry By-Product Meal, Whole Grain Corn
These two panels barely overlap, which is most of the story. 4Health leads with Salmon and Salmon Meal — a fresh named fish followed by its concentrated meal form — then Potatoes, Peas, and Potato Starch. Every one of those five is either a rewarded named protein or a rubric-neutral carbohydrate; none is penalized. Pro Plan opens with Chicken and Rice, which is fine, but its third through fifth slots are Whole Grain Wheat, Poultry By-Product Meal, and Whole Grain Corn. Wheat and corn are the lower-value grain fillers our rubric marks down, and Poultry By-Product Meal is an unnamed rendered protein that scores below a species-named meal like Salmon Meal. So 4Health carries two named proteins and zero demerits in its first five, while Pro Plan carries three penalized ingredients. That contrast — clean fish LID versus a filler-and-by-product tail — is the entire 20-point gap.
Where 4Health pulls ahead
Two named fish proteins up front: 4Health opens with Salmon and Salmon Meal, placing a fresh named protein and its concentrated meal form in the top two slots. Salmon Meal is rendered salmon with the water removed, so it packs more protein into less weight, and because it is species-named you know precisely what it is — not a generic fish or by-product. Our rubric rewards named animal proteins and treats specific meals as a strength, so this opening pairing is the foundation of 4Health’s B (78/100). Pro Plan’s second ingredient is Rice, a carbohydrate, which sits its animal-protein density lower than 4Health’s. For owners who want clearly identified protein — and fish specifically, which suits dogs sensitive to chicken or beef — leading with Salmon and Salmon Meal is exactly the label signal that separates this recipe from the competition. Shop on Amazon →
No corn, wheat, or by-product meal: The cleanest part of 4Health’s advantage is what its first five leave out. There is no Whole Grain Wheat, no Whole Grain Corn, and no Poultry By-Product Meal — the three ingredients that pull Pro Plan down to C (58/100). Instead, 4Health uses Potatoes and Potato Starch as its carbohydrate base, both of which the rubric treats neutrally rather than penalizing. As a limited-ingredient salmon formula, it keeps the panel short and recognizable, which is part of the appeal for owners managing food sensitivities or simply wanting fewer mystery components. None of corn, wheat, or by-product meal is inherently harmful, but on a comparative ingredient grade each one costs points. Avoiding all three while still leading with named fish protein is precisely why a Tractor Supply house brand finishes a full tier ahead.
Higher grade at house-brand pricing: 4Health runs roughly $1.20–$1.55 per pound, while Pro Plan typically sits around $2.00–$2.60. Earning the better ingredient grade for less money is unusual, and it reflects deliberate formulation rather than cost-cutting: Diamond Pet Foods makes 4Health to Tractor Supply’s spec, and the salmon LID recipe spends its ingredient budget on named fish protein and simple carbohydrates instead of cheap fillers. For owners who want a clean, fish-based diet without paying a boutique markup, that combination is hard to beat. Availability is more forgiving than a warehouse club, too — 4Health is sold at Tractor Supply stores and online — though it is still narrower than Pro Plan’s everywhere-reach. If a salmon limited-ingredient formula fits your dog, 4Health delivers the higher rubric score at a noticeably lower price point.
Where Purina Pro Plan holds its own
Grain-inclusive sidesteps the DCM debate: Pro Plan’s recipe is grain-inclusive — it contains rice, wheat, and corn — which means it sits outside the FDA’s grain-free/DCM inquiry entirely. 4Health, by contrast, is a grain-free formula with Peas at position four, and while the FDA’s investigation into a possible link between grain-free legume-heavy diets and dilated cardiomyopathy remains unproven and unresolved, some owners and vets prefer to avoid the question altogether. For those readers, Pro Plan’s conventional grain-and-protein structure is a feature, not a flaw, regardless of its lower ingredient grade. Our rubric does not penalize grain-free recipes or score for DCM risk — it grades the panel — so this consideration lives outside the number. If sidestepping the legume-DCM debate matters to you, that preference can reasonably outweigh a 20-point ingredient gap, and it is the most defensible reason to choose Pro Plan here. Shop on Amazon →
Feeding-trial substantiation: Pro Plan Savor is substantiated through AAFCO feeding trials, meaning dogs were actually fed the diet and monitored, rather than the recipe simply meeting nutrient targets on paper. Our ingredient rubric does not score this, because it grades the panel and not the testing method, but it is a genuine advantage no ingredient list can show. Feeding-trial validation gives many veterinarians and cautious owners added confidence that the food performs in living animals over time — relevant for puppies, seniors, or dogs prone to digestive upset. 4Health’s substantiation is typically formulation-based. If feeding-trial evidence is a firm requirement for you, and for some vets it is, that can reasonably tip the decision toward the lower-scored recipe. Paired with Pro Plan’s grain-inclusive structure, it makes a coherent case for owners who weight clinical testing over label composition.
Vet popularity and buy-anywhere reach: Pro Plan is one of the most veterinarian-recommended mainstream brands, backed by Nestlé Purina’s large-scale quality control and decades of batch consistency — the kind of stability that matters for dogs whose stomachs react to change. The Savor Shredded Blend texture also drives strong palatability, so picky eaters tend to accept it. And it is sold nearly everywhere: pet specialty, big-box, grocery, and every major online retailer, with no membership or specialty-store trip required. 4Health’s higher grade comes with narrower distribution — mainly Tractor Supply and online — which not every owner can reach conveniently. None of this lifts the C (58/100) ingredient grade, but a food your dog reliably eats, that your vet knows, and that you can restock anywhere is a practical strength a score doesn’t capture. Availability and acceptance keep food in the bowl.
The bottom line
On the ingredient panel, 4Health Adult Salmon & Potato earns a B (78/100) and Purina Pro Plan Savor Shredded Blend earns a C (58/100) — a full grade tier apart. 4Health leads with Salmon and Salmon Meal and includes no corn, wheat, or by-product meal; Pro Plan carries Whole Grain Wheat, Poultry By-Product Meal, and Whole Grain Corn, the rubric’s penalties, at roughly higher cost. If you want a clean fish-based limited-ingredient diet, 4Health is the higher-graded pick. But the honest counterweight is that 4Health is grain-free with Peas at position four, and the FDA’s legume-DCM inquiry is still open; Pro Plan’s grain-inclusive recipe sidesteps that question and adds AAFCO feeding-trial substantiation, deep vet familiarity, and nationwide availability. Pick 4Health for the better ingredient grade and a fish LID; pick Pro Plan if you prefer grain-inclusive, want feeding-trial evidence, or need to buy anywhere. Both are sound choices serving different priorities.