myfitnesspal macros and calories calculated how?

sedgrepawk

Hi,
I'm trying to figure out how myfitnesspal calculates calories because I come up with different numbers than the site. I've always been told 1g carb = 4 cal, 1g protein = 4 cal, and 1g fat = 9cal.

When I look at my totals for today, it says i've had 212g of carb, 53 fat, and 163 protein. This should be 212*4+53*9+163*4 = 1977 calories. However, the website and app are reporting 1876 calories --- which is 101 calories less than my calculation. Why?

I'm perplexed because I'm trying to hit a 2000 cal goal per day. The app says I have had the 1876 calories today, thus 124 calories left. It also says the macros remaining are -12 carbs (at too many), 3 fat, and 12 protein. It's just not adding up; 3g fat and 12g protein would be 75 calories total!

Thanks!

japruzze

I tried your calculation method using a few product labels. Using your calculations all the labels had the wrong calorie count! MFP matched the labels for the same foods.

EvanKeel

I'm not sure that MFP does any calculation for the calories based on macros. I always assumed it just uses the total caloric content that was used when the food was added to the database.

Firefox7275

Roughly 4 and 9 kcals a gram.

sedgrepawk

Hmm. Strange. It seems the whole point of myfitnesspal is for numbers to add up. Wish someone from the website could chime in.

TimeForMe99

There is no math in MFP and there really couldn't be. The FDA requires rounding so partial values don't appear. In most cases the rounding is upwards. Also, insoluble fiber is included in the carb grams but excluded from calories. For some foods this can cause a very significant difference. Did you have any fiber or energy bars today? They often have a high amount of insoluble fiber.

Of course, human error can cause rather large errors. If a user enters an item into the database and miskeys or omits a value then the math won't be anywhere close. There are items that have only calories or have a very obvious typo. You may want to check the individual items to see if any appear off.

Finally, alcohol calories will cause the math to go awry, although in the other direction. This fourth category of calories doesn't appear on the tracker but will be in the calories.


If you're a total dork like me and want to read up on the FDA regs, here is the link.

FDA Food labeling guide
http://www.fda.gov/Food/GuidanceRegulation/GuidanceDocumentsRegulatoryInformation/LabelingNutrition/FoodLabelingGuide/default.htm