What is the worst-rated food on Which Dog Food, and why does it score so poorly?

Our expert ratings are based primarily on ingredient quality and nutritional composition, so foods that score poorly tend to share a few common characteristics.

The lowest-rated foods on our site typically contain a high proportion of cereal fillers (such as maize, wheat, or rice in large quantities as the primary ingredient), combined with unspecified meat derivatives or by-products rather than named meat sources. Sugar and artificial additives — including artificial colourings, flavourings, and preservatives — also drag scores down significantly.

Products marketed to mass-market audiences often prioritise palatability and shelf life over nutritional quality, which is why some well-known supermarket brands and budget lines receive low scores. Ingredients like "meat and animal derivatives" without further specification are a common red flag, as they can be sourced from almost anything and vary considerably between batches.

It's worth emphasising that a low score doesn't mean a food will harm your dog in the short term — many dogs live perfectly healthy lives on lower-rated foods. However, our ratings reflect the long-term quality of ingredients and their likely contribution to your dog's overall health and wellbeing.

If you want to see the full range of ratings, you can browse our complete dog food reviews and sort by rating. We'd always encourage owners to read the individual reviews rather than just looking at the score — a three-star food with high-quality ingredients and a specific nutritional purpose may be more appropriate for some dogs than a five-star food.