The scores
Royal Canin Beagle: D (38/100) — Below average. Corn leads, followed by chicken by-product meal, brewers rice, wheat, and corn gluten meal. Double corn and double wheat in one formula.
Diamond Naturals: B (78/100) — Above average. Beef as #1, beef meal as #2, with grain sorghum, ground rice, and ground barley as whole-grain carb sources. Probiotics included.
A 40-point gap spanning two full grade tiers. Royal Canin Beagle is one of the lowest-scoring breed-specific formulas in our database, and it costs more than the food that outscores it by 40 points.
How the ingredients compare
Royal Canin Beagle: Corn, Chicken By-Product Meal, Brewers Rice, Wheat, Corn Gluten Meal
Diamond Naturals: Beef, Beef Meal, Grain Sorghum, Ground Rice, Ground Barley
Royal Canin’s Beagle formula is built on corn (#1) and corn gluten meal (#5) — two corn-derived ingredients bracketing the top five. Wheat at #4 adds another common grain, and wheat gluten appears further down the list. The sole protein source in the top five is chicken by-product meal at #2. This is a corn-and-wheat formula with some by-product meal mixed in.
Diamond Naturals leads with beef (whole fresh meat) and beef meal (concentrated protein), then uses grain sorghum — a more nutritious, less allergenic grain than corn — along with ground rice and barley. Two real animal proteins before any grain, using grains that provide more nutritional value than corn.
Where Diamond Naturals pulls ahead
Real beef first, no corn: Beef as #1 and beef meal as #2 provide two named, high-quality animal protein sources. No corn, no corn gluten meal, no wheat — ingredients that add cheap calories without proportional nutrition. For Beagles, who will eat anything put in front of them, the caloric density and nutritional value per bite matters enormously for weight management.
Probiotics for gut health: Diamond Naturals includes Bacillus subtilis and other probiotic strains for digestive health. Beagles are enthusiastic eaters who occasionally ingest things they shouldn’t, and a healthy gut microbiome provides resilience. Royal Canin’s formula contains no probiotics.
Better value: Diamond Naturals typically costs significantly less per pound than Royal Canin breed-specific formulas. Getting a B-grade food for less than a D-grade food is the rare case where the budget option is also the quality option. The breed-specific label on Royal Canin’s bag doesn’t justify paying more for lower-quality ingredients. Shop on Amazon →
Where Royal Canin Beagle holds its own
The Beagle formula includes psyllium seed husk for satiety — a fiber source that helps dogs feel full, which is directly relevant for the most food-obsessed breed. L-carnitine supports fat metabolism, and the unique Beagle-specific kibble is designed to slow eating (Beagles are notorious inhalers). Pea fiber adds additional satiety support. These weight-management features address the Beagle’s #1 health concern.
GLA safflower oil supports skin health, and glucosamine and chondroitin provide joint support. The formula is clearly designed with Beagle obesity in mind, even if the base ingredients undermine that goal by being corn-heavy.
If your Beagle has a diagnosed weight problem and your vet specifically recommended the slow-eating kibble design, that functional feature has merit. Shop on Amazon →
The bottom line
Diamond Naturals is the clear winner at B/78 vs D/38 — better ingredients, better protein sources, probiotics, and a lower price. For Beagle owners, this is one of the easiest upgrade decisions in dog food: you get dramatically better nutrition while spending less money.
Royal Canin Beagle’s satiety-focused additions (psyllium, L-carnitine, slow-eating kibble) are thoughtful, but they’re built on a corn-and-wheat foundation that undermines the weight-management goal. A slow-eating kibble shape doesn’t compensate for a D-grade ingredient list. Read our full reviews of Royal Canin Beagle and Diamond Naturals for the complete analysis.