Kibble vs. Raw: What Really Happens Inside Your Dog’s Body

If you’ve ever scrolled through a pet forum or chatted with other dog owners, you’ve probably seen one of the biggest debates in the pet world: should dogs eat kibble or a raw diet? Supporters of raw feeding say it’s more natural and healthier, while kibble fans argue it’s safer, balanced, and backed by decades of use. But beyond opinions, what does actual science say?

A team of Finnish researchers decided to find out. They studied how a kibble diet and a raw meat–based diet (RMBD) affect dogs’ health from the inside—specifically, how these diets change things like fat levels, blood sugar, and overall metabolism. The study followed dogs for about 4.5 months, and what they found sheds some light on what really happens in your dog’s body when they eat one type of food over the other.

How the Study Was Done

Researchers worked with 46 Staffordshire Bull Terriers. Half ate regular dry kibble, and the other half ate a balanced commercial raw meat–based diet. Both diets were complete and safe for long-term feeding. The scientists checked the dogs’ weight and blood samples before and after the study. They focused on things like sugar and fat levels in the blood, energy-related changes (how dogs used carbs and fats), and body weight changes over time. This wasn’t about which food tastes better or makes dogs happier—it was about how their bodies responded to what they ate.

What the Researchers Found

After 4.5 months, the dogs eating kibble had higher fat and cholesterol readings in their blood compared to the raw-fed dogs. To put it simply, their blood showed signs of processing more carbohydrates and storing more fat. The researchers think this could be because the kibble contained grains like rice and maize, which are easy for the body to turn into sugar. This doesn’t mean kibble is automatically bad, but it shows how much diet composition can affect what’s going on inside.

How the Raw Diet Affected Dogs

Dogs on the raw meat–based diet had lower sugar levels and higher amounts of ketones, which are compounds the body makes when it uses fat for fuel. In everyday terms, these dogs were likely using fat for energy instead of carbs. That’s similar to what happens in humans on low-carb or “keto-style” diets. They also had slightly lower levels of a hormone called glucagon, which helps control blood sugar. Together, this suggests that raw-fed dogs may have more stable energy and fewer sugar spikes after eating.

Weight Changes and Overall Health

The kibble-fed dogs also gained a bit of extra weight over the 4.5-month period. The raw-fed dogs didn’t show the same trend. Again, this likely comes down to carbohydrates. Kibble diets tend to contain more starchy ingredients, which can lead to slight weight gain over time—especially if dogs are less active. Even though the numbers were different, both diets were generally safe for the dogs. None developed health problems or dangerous blood readings during the study. So, while the raw-fed dogs had leaner metabolic profiles, the kibble-fed dogs weren’t unhealthy—just different in how their bodies processed nutrients.

What It Means for Pet Parents

Kibble is convenient, affordable, and nutritionally balanced, but it’s also higher in carbohydrates. This means dogs’ bodies tend to store a bit more fat and process energy differently. If your dog eats kibble, make sure you’re feeding the right portion size and keeping them active. The raw-fed dogs in the study seemed to burn fat more efficiently and maintain more stable blood sugar levels. That said, not all raw diets are created equal. If you’re considering switching, it’s important to use commercially prepared raw meals that are complete, balanced, and handled safely.

What to Keep in Mind Before Switching

This study looked at one breed, one time frame, and a specific set of diets. Your dog’s age, size, activity level, and health conditions all matter. Before changing diets, especially to raw, discuss it with your vet or a qualified pet nutritionist.

Key Takeaways

This study gives a scientific look at something many pet owners already notice anecdotally—different diets really do affect dogs’ bodies differently. Kibble-fed dogs had higher fat and cholesterol, small weight gain, and more carb-based energy use. Raw-fed dogs had lower sugar levels, leaner metabolism, and higher fat-based energy use. Both diets kept the dogs healthy overall, but they clearly had different effects on metabolism. The researchers concluded that more long-term studies are needed to see whether these differences have lasting impacts on health, such as energy levels, body condition, or disease risk later in life.

Takeaway for Pet Parents

There’s no one-size-fits-all answer to the kibble vs. raw debate. The best diet depends on your dog’s health, lifestyle, and what’s practical for your household. Kibble can be healthy—just choose high-quality formulas and don’t overfeed. Raw can be beneficial, especially for dogs who do well on lower-carb, higher-protein diets. Balance and safety come first. Whether raw or kibble, make sure it’s nutritionally complete and appropriate for your dog’s life stage. Pay attention to your dog’s body. Weight, coat condition, stool quality, and energy are often the best day-to-day indicators of how a diet is working.

This study shows that what your dog eats truly affects how their body runs behind the scenes. Kibble and raw both have their strengths and weaknesses—but neither is universally best. As a pet parent, your job is to find the diet that fits your dog’s needs, your comfort level, and your lifestyle. Feed smart, stay curious, and work with your vet to keep your dog happy, healthy, and thriving—no matter what’s in the bowl.