Does fresh food help dogs live longer? What studies show

Nami is 2.5 years old and hasn't had a vet emergency for 1.5 years – before that, there was an appointment every few weeks because of itching. Fresh food makes the difference.

So far, there's no evidence that fresh food extends a dog's life. The often-quoted “32 months of extra life” comes from a Belgian owner survey from 2003 that wasn't published in a peer-reviewed journal. What studies do clearly show: slim dogs live longer – and fresh food only helps if the ration is balanced.

The question “does fresh food extend a dog's life?” is hotly debated in the dog world. Let's take an honest look – no hype, no marketing: what does the data really say?

Online – including on pet food companies' websites – you often read that dogs fed home-cooked food live almost three years longer. The figure goes back to an analysis of owner reports from Belgium (2003). It wasn't published in a peer-reviewed journal, the data is based on owners' recollections, and other influences such as size, breed, weight or veterinary care can hardly be separated out. That's why it doesn't hold up as evidence.

At the University of Helsinki, the DogRisk project has been collecting questionnaires from dog owners about feeding and health for years. Two analyses are often quoted:

• Allergy and itching: in a study of 4,022 dogs, dogs that as puppies were given more than 20% raw food or less than 80% dry food had fewer owner-reported allergy and itching symptoms as adults.
• Chronic gut disease: dogs that were fed mainly minimally processed, meat-based food as puppies and adolescents were later less likely to have owner-reported chronic gut disease. Dry food during this period was associated with a higher risk.

Important for putting this in context: both are observational studies based on questionnaires. They show associations, not cause and effect – owners who feed fresh food probably differ in other ways too. And these studies say nothing about life expectancy.

Here, the evidence is much stronger:

• Labrador study: 48 Labrador Retrievers were fed in pairs from eight weeks of age – in each pair, one dog got 25% less food than its partner. The leaner dogs lived a median of just under two years longer, and chronic diseases appeared later in them.
• Large-scale practice data: in an analysis of more than 50,000 neutered dogs from twelve breeds, overweight dogs lived shorter lives than dogs of normal weight in every breed.

In practice, this means: whether you feed dry, wet or fresh food – the right amount is the biggest lever. The fresh food calculator shows how much that is for your dog, and if they're already carrying too much weight, our guide to helping your dog lose weight will help.

Three ideas come up again and again in discussions – none of them has been proven for life expectancy in dogs:

Microbiome: food influences the gut flora, and fresh and heavily processed diets encourage different bacteria. Whether this changes health in the long term remains open.

Processing products: strong heating creates what are known as Maillard products. They have been linked to various diseases, but for dogs there's no evidence that they reduce life expectancy.

Heat-sensitive nutrients: some vitamins suffer when heated. Good complete foods make up for this – and home-cooked food has to as well.

Fresh food doesn't automatically mean healthy. One study analysed 200 published recipes for home-cooked dog food: in 95%, at least one essential nutrient was missing in sufficient amounts. Typical gaps are calcium, zinc, iodine and certain vitamins. Chicken and rice alone – the bland diet classic – isn't enough in the long run.

That's why you need:

• a sensible split between meat, vegetables and carbohydrates
• a source of calcium and a suitable mineral supplement
• a source of omega-3 such as salmon oil
• a recipe that has been fully worked out at least once

What this looks like for getting started is explained in the beginner's guide to home cooking. You'll find a comparison of feeding types in dry food, wet food or fresh food.

You don't have to throw everything out. Two approaches work well:

• One fresh meal: for a neutered, normally active 10 kg dog (around 630 kcal a day), you might replace half, for example: around 240 g of home-cooked food plus just under 90 g of dry food.
• Topping: a little cooked vegetable, meat or an egg on top of the usual food – deduct the calories from the main food.

Does fresh food extend a dog's life? So far, there's no evidence for that. Fresh food can be a good choice if the ration is balanced and your dog enjoys eating it. The only thing that's certain: a slim dog fed the right amount has the best chance – whichever bowl they eat from.

The DoggoMeal app calculates fresh recipes for your dog: calcium, phosphorus, omega-3, vitamins – all at a glance and tailored to their weight. Get the app