Credit: Kibble Facts
Fat does not make dogs fat.
A German research team spent seven months proving it by accident. They set out to compare body condition in raw-fed and kibble-fed dogs, and the numbers they collected along the way took apart one of the oldest talking points in pet nutrition. The raw group ate nearly double the fat and finished a full point leaner.
Here is what Leipzig University actually measured.
How the Study Was Built
The setup was strict on purpose.
104 healthy dogs, recruited through veterinary practices in Erfurt, Germany
Ages 2 to 8, each eating one diet exclusively for at least 12 months before enrollment
51 dogs on raw, 53 on commercial kibble or canned food
The same veterinarian examined every dog twice, three to five months apart
Body condition scored on the standard 1 to 9 scale at both visits
Blood, urine, and fecal samples collected each time
Every ration run through a professional formulation calculator against National Research Council recommendations
Age, sex, reproductive status, and body weight distribution showed no difference between the two groups.
The Body Condition Split
Same weight. Different bodies.
Raw-fed dogs: median body condition score of 5, the middle of the ideal range
Kibble-fed dogs: median score of 6, the first rung of overweight
Muscle condition: scored normal in every single dog, both groups
Body weight distribution: no significant difference between groups
The full study reports the body condition difference at P less than 0.001 with a medium effect size. The raw dogs were not skinny. They were carrying less fat on the same frame, which is the entire point of kibble and obesity research and the thing a bathroom scale will never show you.
An earlier Oklahoma State comparison found the same lower body condition in raw-fed dogs, and this one closed the age gap that weakened it.
The Fat Number That Breaks the Rule
Now the part that should end an argument. Here is what was actually in each bowl, measured as a percentage of dry matter.
Crude fat: 28.8% in raw rations against 15.5% in kibble
Protein: 54.1% against 26.7%
Carbohydrate: 5.7% against 46.1%
The raw dogs were eating close to twice the dietary fat and still came in leaner at every measurement.
The rest of the plate explains it. Nearly half of every kibble meal was carbohydrate the dog never needed, while high protein and low carbohydrate is the standard veterinary prescription for canine weight loss. Raw feeders have been running that prescription by default.
Anyone still working from a fat-makes-fat model of macronutrient requirements is arguing with the data.
Kibble Owners Couldn't See It
The researchers asked owners to score their own dog before the vet did.
Raw feeders: scored a median of 5. The vet scored the same dogs 5. No significant difference.
Kibble feeders: scored a median of 5. The vet scored the same dogs 6.
A full point of drift, in one direction, across an entire feeding group. The authors note that owners electing raw tend to be deeper into nutrition and better at reading a body, and that owner and vet scores tend to agree right up until the dog is actually overweight.
Your dog is heavier than you think, and that has been documented for fifteen years.
Where Kibble Overshot
The mineral numbers are where the manufacturing model shows up. Every figure below is coverage of the NRC daily recommendation, kibble first, raw second.
Calcium: 250% against 98%
Phosphorus: 220% against 133%
Sodium: 335% against 133%
Iron: 305% against 169%
Manganese: 336% against 18%
Vitamin E was the loudest result. Seventy-one percent of kibble-fed dogs had serum vitamin E above the laboratory reference interval at the first visit, compared to 12% of raw-fed dogs.
That is not a formulation hitting a target. That is a premix poured in wide to survive extrusion and shelf life, and it is the same logic behind every argument about synthetic nutrients in dry food.
The Two Dials Raw Feeders Should Set
The paper hands raw feeders a short, fixable list.
Iodine came in at a median 13% of the NRC recommendation across raw rations
Manganese came in at 18%
Only about half the raw rations contained fish, seaweed, or an iodine supplement
Calcium to phosphorus ratio averaged 1.0 against a 1.4 target
Thyroid panels came back inside the reference range for every dog in the study, and none showed clinical signs, so this is a formulation detail rather than an emergency.
Add a marine iodine source and check your calcium to phosphorus ratio. An inverted ratio is something adult dogs handle without issue and growing puppies do not. Most owners in the raw group built rations with a free online calculator or by hand, and those two dials are the ones the calculators miss.
What the Bag Is Calibrated For
Read the energy numbers one more time.
Raw-fed dogs received 89% of the recommended daily energy and held an ideal body condition
Kibble-fed dogs received 102% and drifted overweight
The feeding guide printed on a bag of kibble is built from kennel-dog maintenance figures, sold to households with dogs that walk and run and play, and calibrated by a company that sells more product when you pour more of it.
Nobody at that company scores your dog. One veterinarian in Erfurt scored 104 of them, twice, and found the overweight group already knew what it was eating and had no idea what it looked like.
Put your hands on your dog's ribs tonight. The number on the scale has been telling you a different story than the body underneath it.
Sources
1. von Lindeiner LM, Müller SF, Müller E, Heilmann RM, Vervuert I. Lower prevalence of obesity and nutritional imbalances in dogs fed a raw meat-based diet (RMBD) compared to a commercial complete diet. BMC Vet Res. 2026;22:127. https://link.springer.com/article/10.1186/s12917-026-05283-4
2. Hiney K, Sypniewski L, Rudra P, Pezeshki A, McFarlane D. Clinical health markers in dogs fed raw meat-based or commercial extruded kibble diets. J Anim Sci. 2021. https://doi.org/10.1093/jas/skab133
3. Kealy RD, Lawler DF, Ballam JM, et al. Effects of diet restriction on life span and age-related changes in dogs. J Am Vet Med Assoc. 2002. https://doi.org/10.2460/javma.2002.220.1315
