Numbers adding up?

Nick13

Anybody ever do the individual calculations per macronutrient and then put it all together and have it NOT come to 100%?
The carb numbers never seem to match up. I have tried with the fiber, without the fiber, using only 1/2 of the fiber total (like you would for an insulin pump). No dice.
Anyone know why this is or how to adjust it?

Hilary

The calories and the macronutrient values will be a bit off because each food is different in the actual amount of energy (calories) it contains.
What I mean here is that you were probably taught the rule that carbs and protein are 4 kcals per gram, and fat is 9 kcals per gram. They are not. They are close but there is better data on some foods and we use that in the calculations for the macronutrients.
For example, some carbs are 3.8, 4.1, 4.3 kcals per gram etc. Same is true for protein and fats. That is why there will be a discrepancy, when our data is more accurate then the 4-4-9 crude estimation.

Are you using Net Carbs? You can choose to include sugar alcohols in your net carb calculation (or not) in the Profile tab of your account under "Macronutrient targets".

Nick13

I understand all of that. I have the settings where I want them for my personal use, but I also use the software for building for patients in the clinic where I work. It isn't the individual foods that I am having issues with. I say this to patients/clients all the time: "no 2 grapes; no 2 3-oz servings of steak; no 2 medium heads of cauliflower will have the same number of calories, amount of protein, etc., etc." My problem is this:
(I'll use my current project as an example) the completed day of planning (I know, I know: this is a tracking software, not building-but I have developed a way to use it to build meal plans) is 1699 calories and the graph puts it at 7/16/77% but when I actually calculate all or the absolute numbers by hand I come to 3.8/15.9/78.7 (that's carb/protein/fat). The individual considerations don't matter at this level. It's just arithmetic. I have done these calculations on a bunch of the days now and none of them match. I often come to roughly 96%.
For me personally, I don't really care. It just means that I'm getting even fewer grams of net carbohydrate (I'm ketogenic), but for patients and clients, I am trying to be as exact as possible, but when I get through a day of planning and it says 7% carbs, but then I look at it and the absolute grams are WAY below what I am telling these people to eat (in relative terms, I know that 10 g of net carbs isn't a giant difference for most people).
I've been using this software for years going back to school, so I am pretty familiar with all the settings and little quirks and what not. I am just not understanding the discrepancies in the math.

Nick13

Here's another example: a food item that comes to 94 total calories that has 2 net grams carbohydrate, 3.7 grams protein, and 7.1 grams fat. The cronometer calculation comes to 22% carb, 14% protein, 64% fat. By my calculation, that comes to 9% carb, 16% protein, 68% fat. That's 93%. Where is the other 7%?
If I use the Total Carb number, I get 21% carb, 16% protein, 68% fat. That's a grand total of 105%.
Obviously, neither of those is correct and not really even close enough to fudge it in my meal plan documents.

wadegrimm

What is the food item and serving for lastest example. I would like to try the numbers. 👍🤠

Nick13

That one was a recipe for coconut/almond flour tortillas that I saved to my recipes. Could that be the problem?

TheRegents

How are you getting 9% energy from 2 grams of carbohydrate? You can't really just multiply 2 (grams) by 4 (kcal) and divide by 94 (the total energy) if that's what you're doing because different carbohydrates don't all yield 4kcal per gram... that's just a quick approximation of the average energy yielded from all carbohydrates in different foods (in reality some carbs might yield 3kcal, some might yield 5kcal etc)

TheRegents

See table 3.1 here (and compare to table 3.3 and 3.4) for some more detail: http://www.fao.org/docrep/006/Y5022E/y5022e04.htm

Edit:
An applicable quote from the linked page

The conversion factors related to carbohydrate present the greatest problems. The confusion stems from three main issues: The same weight of different carbohydrates (monosaccharides, disaccharides and starch) yields different amounts of hydrous glucose (expressed as monosaccharide), and thus different amounts of energy. In other words, the amount (weight) of carbohydrate to yield a specific amount of energy differs depending on the molecular form of the carbohydrate. This is owing to the water of hydration in different molecules. For example, if expressed as monosaccharide equivalent, 100 g of glucose, 105 g of most disaccharides and 110 g of starch each contain 100 g of anhydrous glucose. Thus, different energy conversion factors have to be used to convert carbohydrate expressed as weight (16.7 kJ/g, usually rounded to 17 kJ/g) and available carbohydrate expressed as monosaccharide equivalents (15.7 kJ/g, rounded to 16 kJ/g) in order to account for the weight difference between the values of these two expressions of carbohydrate (Table 3.4). The calculated energy values for carbohydrates are similar in most cases because the difference in energy conversion factors balances with the difference in carbohydrate values.

and

The use of specific rather than general factors can introduce major differences, which are more than threefold for certain foods.

Nick13

Thanks. After I stepped away from this for a minute, I sort of realized what Hilary was trying to say in the first place. It was this.
My next question, I guess, is: do each and every individual food item (or at least carb-sources) in the database have this level of specificity? I think that, in reality, I was kind of frustrated because I wasn't hitting the numbers that I was expecting...over and over...
Thanks for the input, everyone.