Peer-reviewed research · 2026

What's really in your dog's food?

Excellent

2,384 reviews on

A LANDMARK UNIVERSITY STUDY MEASURED HARMFUL COMPOUNDS IN 41 UK DOG FOODS.
THE RESULTS MIGHT CHANGE HOW YOU THINK ABOUT WHAT GOES IN THE BOWL.

Every time dog food is cooked, a chemical reaction starts. It's called the Maillard reaction, the same process that browns toast and caramelises onions. In small amounts, it's harmless. But when food is blasted at extreme temperatures, it produces harmful compounds, including Advanced Glycation End Products (AGEs), linked to chronic inflammation, kidney damage and accelerated ageing in dogs. And reactive dicarbonyl compounds that can damage DNA. A 2026 study from Hacettepe University, published in the Journal of Animal Physiology and Animal Nutrition, compared these compounds across 41 commercial dog foods available in the UK. It's the most comprehensive analysis of its kind.

Higher heat. More harm.

200-250°C

Highest heat

Kibble

Extruded at extreme temperatures. More than double the lysine damage of fresh food. Acrylamide detected.

Lysine g/kg DM

4.9%

Lysine blocked

CEL mg/kg

120-130°C

Highest AGEs

Wet / Canned / Tray

Retorted under sustained high heat. Highest AGEs and DNA-damaging compounds in the entire study.

128

CEL mg/kg

15.8

Methylglyoxal mg/kg

More CEL than fresh

120°C+ pre-treatment

Hidden processing

Shelf-stable / Freeze-dried

Marketed as “minimally processed”. In reality, it showed the highest early glycation damage and lysine blockage in the study.

4,785

Furosine mg/kg

9.5%

Lysine blocked

3.5x

More glycation than fresh

~80°C

Minimal processing

Fresh (gently cooked & frozen)

Low-temperature cooking locks in nutrition. Lowest harmful compounds. The Maillard reaction stays in its safest, earliest stage.

Lysine g/kg DM

3.2%

Lysine blocked

CEL mg/kg

Illustration of a beagle with a newspaper

The data. Side by side.

Researchers used gold-standard LC-MS/MS laboratory methods to measure harmful compounds across all food types. Here’s what they found.

CEL: the advanced glycation end product that matters most

Of the two AGEs measured (CML and CEL), CEL is the clearer indicator of harmful thermal processing. It’s formed when methylglyoxal (a DNA-damaging compound) reacts with lysine at higher temperatures. The study found that fresh food kept CEL formation remarkably low, even with its high protein content.

CEL (mg/kg dry matter) — lower is better

Fresh

Shelf-stable

Wet

128

Kibble

CEL per unit of protein (mg/kg protein) — lower is better

Fresh

Shelf-stable

186

Wet

333

Kibble

149

Wet food contained over 4x more CEL than fresh. Even adjusting for protein content, fresh food had the lowest CEL of any food type, because gentle cooking stops the Maillard reaction before it reaches the harmful advanced stages.

What about "Shelf-Stable Fresh"?

3.5x

Higher early glycation damage than fresh food

9.5%

Lysine blockage: nearly 3x the damage in fresh

42 mg/kg DM

3-Deoxyglucosone: highest in the entire study

The researchers concluded something had happened to these ingredients before the freeze-drying step, likely a thermal pre-treatment, or ongoing chemical reactions during room-temperature storage.

If it can sit on a shelf for months without a fridge, compromises have been made. Shelf life and freshness are trade-offs, not the same thing.

Why this matters for your dog.

Dogs don't get to vary their diet the way we do. Most eat the same food at every meal, every day, for years. If that food contains elevated levels of AGEs and reactive compounds, those exposures accumulate over a lifetime.

Research has shown that dogs fed higher-AGE diets had elevated AGE concentrations in their blood plasma. These compounds aren't just passing through. They're being absorbed, building up, and driving persistent low-grade inflammation.

How your dog's food is made matters just as much as what's in it.

Fresh, gently cooked, frozen fast.

At Different Dog, we cook with real ingredients at low temperatures and freeze immediately, locking in nutrition and stopping harmful compounds before they form.

Source: Kocadağlı, T., Clarke, C. & Gökmen, V. (2026). A Comparative Analysis of Maillard-Derived α-Dicarbonyl Compounds and Advanced Glycation End Products in Fresh, Wet, Kibble, and Freeze-Dried Dog Foods. J. Anim. Physiol. Anim. Nutr. doi: 10.1111/jpn.70053. Open access, peer-reviewed.

What's really in your dog's food?

A LANDMARK UNIVERSITY STUDY MEASURED HARMFUL COMPOUNDS IN 41 UK DOG FOODS.THE RESULTS MIGHT CHANGE HOW YOU THINK ABOUT WHAT GOES IN THE BOWL.

Higher heat. More harm.

Kibble

Wet / Canned / Tray

Shelf-stable / Freeze-dried

Fresh (gently cooked & frozen)

The data. Side by side.

CEL: the advanced glycation end product that matters most

What about "Shelf-Stable Fresh"?

Why this matters for your dog.

Fresh, gently cooked, frozen fast.

Higher heat. More harm.

Kibble

Wet / Canned / Tray

Shelf-stable / Freeze-dried

Fresh (gently cooked & frozen)

The data. Side by side.

CEL: the advanced glycation end product that matters most

What about "Shelf-Stable Fresh"?

Why this matters for your dog.

Fresh, gently cooked, frozen fast.

A LANDMARK UNIVERSITY STUDY MEASURED HARMFUL COMPOUNDS IN 41 UK DOG FOODS.
THE RESULTS MIGHT CHANGE HOW YOU THINK ABOUT WHAT GOES IN THE BOWL.