The environmental impact of pet food is no great secret, with the process of taking animal products and packaging them into house-friendly feed for our cats and dogs being an energetically expensive process. As we all look to do our part for the planet, which type of pet feed is better for the environment? Wet, or dry?

New research has weighed in on the issue, looking at the nutritional values and environmental pawprints of different types of feed for cats and dogs. It looked at a total of 938 diets (618 for dogs, 320 for cats) encompassing wet, dry and homemade food to assess their macronutrient profiles and value as an energy source.

The study also assessed the feed types’ annual environmental impacts, including emissions and water and land use. They were able to calculate this using averages for the amount of food consumed per year – though, as anyone with a retriever will know, this can vary.

Their results showed that across the board, dry foods came out better for the environment compared to wet food. Dry food also provided the most energy per gram, though high-energy foods aren’t necessarily an indication of high-nutrient foods.

Wet pet food had a greater environmental impact, though homemade varieties sometimes had a lower pawprint by comparison. That said, the amount of water usage was about equal for both. One pro for wet food, however, was that it had higher levels of protein, but getting this entails using up twice the energy needed to make dry food.

By their calculations, the researchers estimate that a 10-kilogram [22-pound] dog’s annual impact would represent 12.4 percent of that of a Brazilian citizen if they were on a dry diet. If they were eating wet food, that jumps to 97.8 percent of the equivalent emissions.

Previous research suggested that a vegan diet for dogs might be the "healthiest and least hazardous," provided we store it right which, apparently, most of us aren't.

If you’re looking for a way to lower your footprint, getting your furry friends in on the good fight could be a good place to start by switching to a nutritious brand of dry food.

There’s no “one feed fits all” rule when it comes to living animals, all of whom will have different medical and nutritional needs that must be taken into account. However, for animals with flexible diets, swapping out the wet stuff for dry food could be a simple way to support the fight against the climate crisis.

It should also serve as motivation for pet food manufacturers to seek to create more sustainable solutions to pet food production. The study provides suggestions here, with finding alternative protein sources such as insects being one, though they recognize that the availability of these varies worldwide.

Considering some cats’ love of eating spiders, and that most dogs will put just about anything in their mouths, we expect they’d be up for the culinary challenge.

The study was published in Scientific Reports.