I didn't want to get into the weeds so much deep in the comments on Lemmy, but here we are:

Responses

For example, they don’t count anything listed only as “protein” as protein because they don’t trust the manufacturer not to lie on the label.

I don't think it's fair to call this a bias. If it was real protein, they would proudly put what kind on the label so it's likely something like textured soy protein.

Given that this site gets literally all of their information from the manufacturer’s label, I’m sure you see why that’s a problem.

As I understand it, she's gotten a lot of her information from the data sheets sent to larger distributors like chewy.com as well, which are much more accurate and provide additional information not included on the packaging, such as the amount of ash and carbs.

Their information is also just plain wrong on some accounts, such as labeling Royal Canin as “significantly lower carbs than average” while most experts agree the opposite is true.

If you had actually read what was written, it says, "of 51 products, only 10 had fewer carbs than average". Perhaps it is poorly worded, but the implication there is 80% of the products are actually higher carbs than average.

The reason they get these wrong is due to a flawed methodology.

Again, they got it right. You just didn't read it correctly.

What to do next

With all of that being said, you should be using that side as a recommendation for where to start, and if you are taking your pet food choices seriously, you should do your own research by figuring out the most current dry matter basis values for the particular food you're looking at.

Here is an article that explains how to do that: https://endocrinevet.removed/2014/01/how-to-calculate-carbohydrate-and.html

I personally use this handy online calculator to speed up the math a little bit: https://balance.it/convert

The catch is unless you know the exact ash content, which is almost never listed on the packaging sold to consumers, you have to guess, which greatly distorts the total carbohydrates. The best way I have found to get the exact ash content it to just go to chewy.com and look at the consumer questions because someone has likely already asked and use that value, or ask the question yourself and chewy will respond within a day or two.

Also, since at the end of the day these dry matter basis values are completely arbitrary unless you have something to compare them against, I recommend looking at data sheets put together by zoos where they have identified the dry matter basis of various prey species for use in feeding at zoos.

https://www.rodentpro.com/informationcenter/resources/nutrient-composition-of-whole-vertebrate-prey

https://www.semanticscholar.org/paper/NUTRIENT-COMPOSITION-OF-WHOLE-VERTEBRATE-PREY-FISH)-Dierenfeld-Alcorn/9119b1ba4e298635227d69da95636d920eb4b6e9

My take on the subject is you want (in dry matter basis) a breakdown of something like 66-75% protein 25-33% fat and as little ash and carbs as you can get. Wet foods typically don't have much ash. Dry foods have a lot more. Cats are obligate carnivores so they should have zero carbohydrates.

It's legit. Her only fault is the data is always slightly out of date because pet food manufacturers are always changing their recipes, which change the dry matter basis values and warnings about ingredients.

It's all explained on her about page, but basically she has painstakingly built up the database by sourcing everything herself and accepting some community input. I personally have emailed to have things updated.

https://catfooddb.com/about