The scores
Eukanuba Puppy Medium Breed Chicken: B (75/100) — Very Good. Named chicken first, chicken by-product meal second, and a grain stack of corn + wheat + corn grits. Engineered around the 3D DNA research program Mars runs for Eukanuba.
Iams ProActive Health Smart Puppy Original with Chicken: B (75/100) — Very Good. Named chicken first, then ground whole grain corn, chicken by-product meal, and a grain stack of corn + sorghum + beet pulp. Mars’s value-tier puppy formulation.
How the ingredients compare
The top five ingredients:
Eukanuba Puppy Medium: Chicken, Chicken By-Product Meal, Corn, Chicken Fat, Wheat
Iams Smart Puppy: Chicken, Ground Whole Grain Corn, Chicken By-Product Meal, Ground Whole Grain Sorghum, Dried Plain Beet Pulp
Both formulas open with fresh chicken and use chicken by-product meal as a core protein contributor — an intentional Mars formulation choice that delivers organ-meat density at value-tier cost. By-product meal is AAFCO-defined as clean, rendered parts of the carcass excluding feathers, hair, horn, teeth, hooves, and digestive-tract contents. Nutritionally it’s dense in bioavailable nutrients, though the name is off-putting to many consumers.
The structural difference is in the grain stack. Eukanuba puts corn in position three and wheat in position five, with chicken fat wedged into position four — a higher-protein, higher-fat macro profile suited for a medium-breed puppy’s metabolic demands. Iams puts corn in position two (right after the fresh chicken), then by-product meal in three, sorghum in four, and beet pulp in five — a more carbohydrate-heavy opening suited for the broader mainstream-puppy market where Iams plays.
Further down, Eukanuba adds corn grits, chicken flavor, fish oil, flaxseed, dried beet pulp, an extensive vitamin/mineral premix, and the 3D DENTADEFENSE (proprietary dental additive) + DHA package. Iams adds chicken fat, egg product, natural flavor, fish oil, flaxseed, and a DHA + prebiotic-fiber premix. Both hit the puppy-nutrition fundamentals — DHA from fish oil for brain development, appropriate calcium:phosphorus, prebiotics (beet pulp) for sensitive puppy digestion.
Where Eukanuba Puppy pulls ahead
Higher protein + fat macro profile: Eukanuba Puppy Medium delivers 30% protein / 20% fat minimums, notably above Iams Smart Puppy’s 28% protein / 17% fat. For working-breed puppies and more active medium-breed households, the higher energy density matches metabolic demand better.
Chicken fat in position four: Fat in the top five means energy-dense macronutrients lead the formula — appropriate for a puppy’s growth energy requirements. Iams delays chicken fat deeper into the ingredient list.
DENTADEFENSE dental package: Eukanuba adds a proprietary dental-plaque-reducing additive (often sodium hexametaphosphate or a kibble-texture design) that Iams doesn’t include. Modest benefit, but worth mentioning. Shop on Amazon →
Where Iams Puppy holds its own
Price per pound: Iams Smart Puppy is materially cheaper than Eukanuba on retail channels — often 25–35% less at Walmart, Target, Amazon, and most grocery chains. For owners of larger litters, foster puppies, or rescue-group feeding programs, the budget delta compounds fast.
Wider retail distribution: Iams is stocked at virtually every grocery store, big-box retailer, and pet specialty store in North America. Eukanuba’s distribution skews to pet specialty and breeder channels — harder to find in a pinch.
Sorghum + beet pulp fiber architecture: Sorghum is lower on the glycemic index than corn, and beet pulp is a well-tolerated prebiotic fiber that supports sensitive puppy stomachs. Iams’s choice here isn’t accidental — the Smart Puppy line targets the mainstream-owner buyer whose biggest feeding anxiety is inconsistent stools. Shop on Amazon →
The bottom line
For an active medium-breed puppy or a working-breed household, Eukanuba Puppy Medium Breed is the slightly more performance-oriented pick at a modest premium. For the budget-conscious household or anyone already buying Iams from a grocery run, Iams Smart Puppy delivers the same score at a lower sticker price with wider availability. Both are Mars Petcare formulations made in the same quality-control ecosystem, and the one-brand-vs-the-other decision is mostly about shelf positioning and marketing target. See our best affordable dog food guide for a broader comparison.