Kimberly and I were at Costco this morning picking up a pizza, among other things, when we noticed that there was no nutrition information on the pizza box. Costco does provide cooking instructions, a list of ingredients, and a warning about allergens (“contains: wheat, milk, soy”) but really nothing about calories, fat, or salt content per serving. It occurred to me that I could ball-park the calories part with a fairly simple analysis, though I couldn’t do much about the latter two without a lab setup. Here’s my calorie analysis:
We start with a Costco 16″ Round “Take & Bake” Pepperoni Pizza. Based on the size, we typically cut it into eight pieces, so my analysis will assume that a serving is 1/8th of the complete pizza. According to the Costco packaging, a whole pizza has a net weight of 44 ounces (or 1247.4 grams) so a single slice is 5.5 ounces (155 grams). Just to double-check, I weighed a single piece that we had cut and found it to be 151 grams. Hey, did Costco shortchange us on the pizza?!? No, it is probably more likely that I’m just not roboticaly perfect on cutting a pizza. Anyway, I weighed my slice both before and after cooking (according to the recommended instructions) and discovered no noticeable weight difference so we can assume the consumed weight of a serving of Costco pepperoni pizza is about 155 grams.
Now, if we just want an upper limit for the number of calories, we can easily calculate it because the highest density of calories within any food ingredient is 9 calories/gram. (Note that I’m using food calories.) So my 155 grams per slice means that there are no more than 1395 calories per slice of pizza. Before you panic and swear off Costco pizza, remember this is only an upper limit, a piece could have much less. And indeed, we’ll see with further analysis that it very, very likely does.
To get a better number, I assumed my Costco pizza was composed of a few major components: dough, tomato sauce, cheese, and a number of 3″ diameter pieces of pepperoni. I then measured the relative weight of each of these components in a single slice and looked up calorie counts for each. Here’s what I came up with:
|about 3.5 pepperoni slices||7 g||33|
|a “bunch” of mozzarella cheese||24 g||61|
|a “healthy spreading” of tomato sauce||33 g||16|
|a large triangular, flat, piece of dough||91 g||208|
This puts our total at only 318 calories for a single serving (one slice, 155 g) of Costco pepperoni pizza!
It should be noted that the calorie densities used to arrive at this number are for products that may be different than what Costco uses. (In the table above are links to the sources for the numbers I’ve used.) This is particularly important if Costco uses products, or makes from scratch, versions that contain more sugar and/or fat. In which case, my number of 318 calories per slice is low.
For comparison, Pizza Hut’s published calorie counts for pan pizzas average 384 calories per 155 g serving. (For the record, they also consider a serving to be 1/8th of a pie.) Likewise, Papa John’s nutritional info puts a pepperoni pizza serving at 385 calories per 155 g. It should be noted that I normalized their published statistics to the same size as our Costco piece so we really are comparing apples-to-apples here. As a result, I feel like we’re in the ballpark on the Costco number.
For additional reading on how to measure calories:
- Burn A Peanut
UPDATE 2008.06.06: I’ve added another post with information from Costco regarding the actual calorie and nutrition information for all of their pizza varieties. Dave wasn’t that far off in his estimate but now you can get the info for all of the different 16″ pizzas Costco sells.