Merrick Grain Free Beef & Sweet Potato Puppy Food

10 ingredients in this list are ones we hold sourced evidence on , and 3 of them are genuinely contested rather than merely unpopular online.

• Potato · ingredient 4ContestedA starchy tuber used as the carbohydrate base in many grain-free foods (it is a vegetable, not a cereal grain). The FDA's open 2018 investigation into diet-associated canine DCM listed potatoes 'in various forms' as main ingredients of interest alongside pulses such as peas and lentils.
• Peas · ingredient 5ContestedA pulse (legume) used in many grain-free foods as a plant protein and carbohydrate source. Peas are central to an open FDA investigation, begun in July 2018, into a possible link between diets high in peas, other pulses, and potatoes and canine dilated cardiomyopathy (DCM); 93% of reported products contained peas and/or lentils.
• Pea protein · ingredient 9ContestedA concentrated protein fraction extracted from peas, used to raise a food's protein content without added meat. As a pea-derived pulse ingredient it falls within the group of legume ingredients examined in the FDA's open 2018 investigation into diet-associated canine DCM; metabolomic work has flagged pea-related compounds, but causation has not been shown.
• Named Muscle Meat (e.g., Deboned Chicken, Beef, Salmon) · ingredient 1Well supportedA named fresh muscle meat identifies both the species and that it is clean flesh (AAFCO defines 'meat' as the clean flesh of a specified slaughtered mammal, and 'poultry' as clean flesh and skin). Naming the species is what lets an owner verify a protein for allergy avoidance.
• Named Meat/Poultry Meal (e.g., Chicken Meal, Lamb Meal) · ingredient 2Well supportedA rendered, water- and fat-reduced concentrate from a named species (AAFCO, e.g., 'chicken meal'). Because most moisture is removed it is a dense protein source (poultry meals commonly around 57-69% crude protein) and it names the species for allergy avoidance.
• Fish oil (EPA + DHA omega-3) · ingredient 12Well supportedMarine-source omega-3 fatty acids (EPA and DHA) from fish oil. A randomized, double-blinded controlled trial (Roush 2010) found improved weight-bearing in dogs with osteoarthritis, and a 2022 meta-analysis identified clear clinical analgesic efficacy for omega-3-enriched diets and supplements.