Confused by food label comparisons

[Debb, Lucy & Oscar]

I've got that cold that's going around and I admit my brain is in a kind of pea-soup-thick fog today, but I just tried using the Dog/Puppy Food Calculator with Cost Calculator on both Fromm's Game Bird food and Acana's Lamb and Apple food. Its got my brain spinning in confusion over the numbers. Something seems very wrong.

With Fromm's Game Bird the numbers come out to: 4,047 kcal/kg and 409 kcal/cup. With Acana's Lamb and Apple the numbers are: 3505 kcal/kg and 421 kcal per cup. How is it possible that Fromm's has more kcal's per kg than Acana, but less kcal's per cup??? Is there something I'm not getting? Is it that I'm not understanding metrics right?

Here's are the pages from which I'm getting the numbers:

http://www.acana.com/wp-content/uploads/2013/01/LambAppleFactSheet_...

http://frommfamily.com/products/four-star/dog/dry/grain-free-game-b...

[Karen, Jasper and Jackdoodle]

I am clueless about metrics, but I agree that this doesn't make sense. I'll try to look into it when i have a chance.

Meanwhile, maybe someone else with knowledge on this will chime in. 

[Karen, Jasper and Jackdoodle]

Apparently, there is no fixed number of cups per kilogram, because kilograms are a measure of weight. Cups are a measure of volume. So that may have something to do with it. 

[F, Calla & Luca]

Exactly. You are comparing apples and game birds : ) It would make sense to see the recommendations of cups per given weight of dog, since the calories are approximately the same per cup. Then you need to find out how many cups per bag. Alternatively you could figure out the G per cup. The Acana bag I just looked out says there are 120 G per cup.
Acana Wild Prairie says the largest bag will feed a 44pound dog for 72 days. If Fromm has a similar statement it makes it easy.

[Stephanie and Ragley]

Ok- I just did the math and I think I'm correct on the numbers. I suspected, like Karen, that it had something to do with density so I checked out the sites and crunched some numbers:

In every 1 kg of Acana, there are 8.33 cups of food
In every 1 kg of Fromm, there are 9.89 cups of food

What I take from this is that Acana is perhaps more dense than Fromm, so it can weigh the same, but more food fits per cup and thus more calories per cup. Someone please check my math though haha

[J and Riley (and Luna)]

Well we came to the same conclusion, so we must be right, right? ;)

[J and Riley (and Luna)]

Using my fancy Canadian Chemistry teacher voodoo I have determined that the Acana formula is denser than the Fromm.  

Fromm = 0.404 g/mL   (0.101 kg/cup)

Acana = 0.480 g/mL   (0.120 kg/cup)

The difference in density explains why they don't have the same volume/mass measurements :)  It would be like comparing the calories in a cup of popped popcorn vs. a cup of unpopped popcorn kernels.

[Debb, Lucy & Oscar]

Great deductive reasoning, ladies! Volume vs. weight. Makes perfect sense now. Thank you all so much!

[Ronna, Murphy & Wilson]

Also if you look at both labels the Fromm is using a standard 8 ounce cup measurement which equals 236.5 ml and the Acana is using a 250 ml cup measurement. So the cup sizes are actually different.

[Debb, Lucy & Oscar]

You're absolutely right! Fromm is a little under a cup and Acana is a little over a cup. Wasn't there a time back in the '70's when the US was suppose to convert over to the metric system? I remember hearing about it in one of my jr. high classes. It never really took hold though. So now we have to deal with trying to convert metric to US standards of measure. It just doesn't work in a lot of cases.

[J and Riley (and Luna)]

I have no idea why the U.S. hasn't converted to metric, makes no sense to me.  The entire Scientific community and most of the International community uses Metric.

[F, Calla & Luca]

Well, for many years I've been exposed to both but I still think in English measures. It would cost billions to convert things never mind people, that's why : )

[J and Riley (and Luna)]

Yeah I guess so... I'm sure they could find the money if they REALLY wanted to, but they have things higher on the priority list :p