Nulo Challenger Dry DOG FOOD Review

With an average score of 5.4, Nulo Challenger Dry is considered a moderate risk dog food. There are 5 recipes that average 34% protein and 27% average carbohydrate as calculated. 

This line loses food quality points for its somewhat high carbohydrate content. The Large Breed Puppy Recipe is higher at 32%, with a lower protein content as well. Dogs have no nutritional requirement for carbohydrate but starch is required for extrusion in dry foods like these. Excessive carbohydrate is an indicator of food quality as it can be used to reduce manufacturing cost. Large amounts of starch can increase insulin levels, cause obesity and negatively impact gut health. 

This line also loses significant ingredient quality points for added amino acids plus vitamin and mineral premix. Ideally, these nutrients should come from whole food sources and their inclusion  is usually due to poor quality or overly processed ingredients. Vitamin and mineral excesses, especially vitamin D and copper, can also result from vitamin premixes.

The food safety score is lower because, like all kibbles, Nulo Challenger Dry is ultra-processed. The individual ingredients in dry dog foods are heated several times during processing, which can cause a significant loss of enzymes, vitamins, amino acids and phytonutrients. Ultra processed foods are often supplemented as we see here. Processed foods are also linked to higher mortality rates in many species. 

Rounding out the food safety scores, the line loses a point for a high pesticide or herbicide ingredient (dried spinach) … although it’s worth notion this is a glam ingredient (see below) that’s present in a very small amount, and most of the other produce in this line is organic. Thes line also loses a point for added natural flavor. This ingredient is often animal digest or MSG, which are both low quality ingredients with limited safety studies.

The line contains sodium selenite as a source of selenium. Dogs need selenium, and it’s usually added in very small amounts. However some research suggests that sodium selenite may be associated with potential toxicity, so selenium yeast is the preferred form of this mineral.   

The inclusion of “glam” ingredients like blueberries, pumpkin and spinach is also a concern. These ingredients are added to make consumers think the food has healthy ingredients. But they’re listed below the salt, which means they’re present in tiny amounts that won’t benefit your dog. 

It’s worth noting that Nulo adds and guarantees a decent amount of probiotics in the food. 

There’s no indication whether fish ingredients are farmed or wild-caught. Farmed fish is less nutritious, with a less favorable fatty acid balance. The label does not provide the omega-6:omega-3 ratio, which is a concern since AAFCO allows a very inflammatory ratio of 30:1.