? Question about Calculating % Calories from Carbs

[Wulfwin]

So I've been trying to calculate % of calories from carbs on some foods (I'm trying to find a novel protein/LID low carb dry food to transition my cat Rain to while I work on getting her to a wet food diet - the wet food transition is probably going to take months). I've been using the calculator at http://scheyderweb.com/cats/catfood.html and the question that I have is with the "Ash/other minerals" box. If a food has a total of 2.7% guaranteed analysis of taurine/omega 6/omega 3, are those things that go in that box? I assumed so since they're the only other things listed on the guaranteed analysis as percentages.

For instance, Wysong Epigen Venison (not Epigen 90, as that has chicken in it) the guaranteed analysis lists:
Crude Protein 61%
Crude Fat 10%
Crude Fiber 4%
Moisture 10%
Taurine 0.2%
Omega 6 Fatty Acids 2.3%
Omega 3 Fatty Acids 0.2%

Plugging that into the calculator, and following the explanation posted by April (manxcat419) on another thread (100 divided by total calories (344) multiplied by calories from carbs (43)) , I get 12.5% calories from carbs. Am I doing that calculation correctly?

 

[Elizabeth and Bertie]

Hi Sarah,

I think the way I usually describe the calculation is slightly different to April's but 'all roads lead to Rome'....
(apologies for copying and pasting the paragraph below from another post):

Calculating carbs with online carb calculator
http://scheyderweb.com/cats/catfood.html
The above is a very nifty tool.
If you enter the percentages for protein, fat, ash, fibre and moisture from the cat food label it will calculate the calories from carbs per 100g of food. If you want to go further and calculate the ‘percentage of calories from carbs’ you just grab a calculator and do this: Divide the calories from carbs per 100g by the total calories per 100g, and then multiply by 100. Bingo!

When I'm doing a calculation for wet foods I don't include the additional minerals (in the ash content) because the amount is so negligible. But if I'm calculating for a dry food I've found that adding or not adding the minerals can affect the carb content a little bit, so I do often add the minerals (calcium and phos) to the ash content in dry food calculations (but not the omega oils). Sometimes I do the calculation with and without the additional minerals to see how it affects things...

The things that you would add into the ash box are the things that are taking up space in the food but that don't have a calorie value.

If your 'guaranteed analysis' is a guarantee of minimum and maxium values, then that may or may not be an accurate representation of what is in the food at any given time: And for that you'd need to contact the manufacturer and see if they can give you either the 'current as fed' values or even the 'typical analysis'. Manufacturers vary in their willingness to be helpful in this regard....

In the absence of 'current as fed values' or 'typical analysis', the 'guaranteed analysis' (of minimum/maxium values) can still be helpful in giving you a ballpark figure; but it is also always important to look at the ingredients list for any source of carbs or sugars...

At the end of the day, all our carb calculations give 'approximate' results, they're an 'educated guess'.
The recipes change over time, each batch of food may have a slightly different mix/balance of ingredients, the meat in the product may be fatty or it may be lean, etc, etc, etc.

We do the best we can to calculate the carb values, but ultimately it is the effect on our cat that determines whether the food is OK or not...

Incidentally, I have an Excel document that calculates carb values. It's very basic, but effective. If you'd like me to send it to you then just PM me your email address.

Eliz

 

[Wulfwin]

Hi Eliz,

Thanks for the reply! That does clarify things for me. I tried the calculation again without the taurine/omega oils, and got 15% as a ballpark figure. Which is certainly better than the about 40% I get for the hydrolyzed protein! I think I'll get a bag and see if she'll take to it (and if she doesn't start vomiting again).

I'll take you up on that offer of the excel document, thanks!

 

[Elizabeth and Bertie]

I'll take you up on that offer of the excel document, thanks!

Done!
.