The scores
Blue Buffalo Life Protection: B (78/100) - Above average. Two named animal proteins lead the formula, backed by brown rice, oatmeal, and barley.
Iams ProActive Health: C (63/100) - Average. Chicken is first, but corn grits at number two and by-product meal pull it down.
How the ingredients compare
The top five ingredients make the gap obvious:
Blue Buffalo: Deboned Chicken, Chicken Meal, Brown Rice, Oatmeal, Barley
Iams: Chicken, Corn Grits, Ground Whole Grain Sorghum, Chicken By-Product Meal, Dried Beet Pulp
Blue Buffalo has two named animal protein sources before any carbohydrate appears. Iams has one, then immediately drops into corn grits - a refined corn product that's cheap filler with minimal nutritional value. By the time you reach position five, Blue Buffalo has given you two proteins and three quality whole grains. Iams has given you one protein, two grains (one of them corn), a by-product meal, and a fiber source.
The grain quality is a stark difference. Brown rice, oatmeal, and barley are whole grains that provide fiber, B vitamins, and slow-release energy. Corn grits is a stripped-down corn product that exists because it's cheap. These two formulas aren't playing the same game.
Where Blue Buffalo pulls ahead
Protein depth: Deboned chicken plus chicken meal means Blue Buffalo has serious animal protein concentration in the top two slots. Chicken meal is roughly 3x more protein-dense than whole chicken since the water is already removed. Iams has chicken first (good), but then doesn't see another animal protein until chicken by-product meal at position four - and by-product meal is a step down in quality.
Grain selection: Brown rice, oatmeal, and barley versus corn grits and sorghum. This isn't close. Blue Buffalo's grains are nutrient-dense whole grains used for their nutritional value. Iams' corn grits are there because they're one of the cheapest carbohydrate sources available.
Omega-3 source: Blue Buffalo includes flaxseed, a plant-based omega-3 source for coat and skin health. Iams has no dedicated omega-3 ingredient - no fish oil, no flaxseed. For long-term coat and skin health, that's a meaningful gap. Shop on Amazon →
Where Iams holds its own
Price is Iams' strongest argument. It's significantly cheaper per pound than Blue Buffalo - often half the cost per bag. For families feeding multiple dogs on a tight budget, that difference is real. Iams covers the nutritional basics at a genuinely accessible price point.
Iams also includes FOS prebiotics for digestive health, which is a useful functional ingredient that not every brand at its price tier offers. Dried beet pulp, despite its unglamorous name, is a solid prebiotic fiber that supports healthy digestion.
The brand has been around since 1946 and has a long track record. It uses mixed tocopherols (natural vitamin E) as a preservative rather than artificial BHA or BHT. The vitamin and mineral panel is comprehensive. If your dog is healthy and thriving on Iams, it's not an emergency - it's a functional food that gets the job done. Shop on Amazon →
The bottom line
This is the classic grocery-store-to-pet-store upgrade, and the numbers confirm what the ingredient lists suggest: Blue Buffalo is categorically better. A 20-point gap across a full letter grade isn't a close call. Blue Buffalo's double chicken protein base and quality whole grains outclass Iams' corn-heavy, by-product-reliant formula in every meaningful way.
Blue Buffalo costs more per bag - that's the tradeoff. But if your budget allows the step up, the ingredient quality difference is among the largest we've measured between any two mainstream brands. Read our full reviews of Iams and Blue Buffalo for the complete breakdown.