math off in MFP?

juliebeannn

So I discovered something a little strange in MFP today. I'm a little bit of a nerd and track macros and calories in a spreadsheet. Up until now, I always just logged in my spreadsheet the total numbers from MFP (cals and macros) at the end of each day.

Today, while killing time at work (hehehe), I decided to plug in some formulas and was surprised at how different the total calorie number was.

Let me break it down. For example, today:

Carbs: 85 (x4 = 340 cals)
Protein: 126 (x4 = 504 cals)
Fat: 79 (x9 = 711 cals)
total calories from MFP: 1513 (total 1555 cals)

So if carbs and protein are 4 cals per gram each and fat is 9 calories per gram, I get a total of 1555 calories for the day, not 1513.

I know 40 calories isn't a huge deal. But, I ran the formula for a full week and the difference varied from 40 calories under-reported (ie. above example), but yesterday turned out to be a 168 calorie difference (MFP: 1704 Macro math: 1536).

What's the deal? Am I doing something wrong?

I know this might not be the right forum for this question, but I thought I'd throw it out here.

SideSteel

So I discovered something a little strange in MFP today. I'm a little bit of a nerd and track macros and calories in a spreadsheet. Up until now, I always just logged in my spreadsheet the total numbers from MFP (cals and macros) at the end of each day.

Today, while killing time at work (hehehe), I decided to plug in some formulas and was surprised at how different the total calorie number was.

Let me break it down. For example, today:

Carbs: 85 (x4 = 340 cals)
Protein: 126 (x4 = 504 cals)
Fat: 79 (x9 = 711 cals)
total calories from MFP: 1513 (total 1555 cals)

So if carbs and protein are 4 cals per gram each and fat is 9 calories per gram, I get a total of 1555 calories for the day, not 1513.

I know 40 calories isn't a huge deal. But, I ran the formula for a full week and the difference varied from 40 calories under-reported (ie. above example), but yesterday turned out to be a 168 calorie difference (MFP: 1704 Macro math: 1536).

What's the deal? Am I doing something wrong?

I know this might not be the right forum for this question, but I thought I'd throw it out here.

You would have to check individual entries to see which selections you could be making that do not add up. I don't recall exactly how the whole "net carbs" thing works between fiber and carbohydrate but that can screw things up as well.

ryry_

the inaccuracies typcially come from food manufacturers and rounding on food labels.

FDA allows rounding per the variables below (copied from fda.gov), so companies will round down as they are allowed, which throws off the counts between macros and total calories.

Nutrient Increment Rounding
< 5 cal - express as 0
≤50 cal - express to nearest 5 cal increment
> 50 cal - express to nearest 10 cal increment

Similar rounding is allowed in macros as well.

juliebeannn

Oooo! I get it. Hehe. Thanks!

GetSoda

Labeling rules also allow manufacturers of food to NOT include calories from sugar alcohols or insoluble fiber.
That's the reason you might see 20 carbs on something, but it's only 64 calories.

(insoluble fiber is fiber that isn't typically digested.)

Look at a Quest bar label for a good example of this.

bumblebums

Specific to MFP is another rounding problem. They write code for various platforms, and rounding is not handled the same way in all of them, so you get slightly different numbers for macros. It's a bug they are supposed to be fixing, actually (I reported the issue I noticed when looking at the macros in the Reports feature and in my diary.)

Sarauk2sf

The other thing that can impact the math is fiber. Fiber, while counted in carbs, actually has about 2.5 cals per gram (depending on the type).

cmeiron

The other thing that can impact the math is fiber. Fiber, while counted in carbs, actually has about 2.5 cals per gram (depending on the type).

Ok, this is good to know. I recently started paying more attention to my fibre, and have upped it considerably. Last night, when planning today's food, I noticed that my macros were all bang-on or slightly over, yet I was below my calorie goal. This left me scratching my head. How should one account for this in their calories for the day, then?

jonnythan

MFP doesn't actually calculate calories from macros. It only adds up the calories from the individual foods entered.

cmeiron

MFP doesn't actually calculate calories from macros. It only adds up the calories from the individual foods entered.

So does the inconsistency come from MFP or from the way the foods are entered?

jonnythan

MFP doesn't actually calculate calories from macros. It only adds up the calories from the individual foods entered.

So does the inconsistency come from MFP or from the way the foods are entered?

It comes from whatever the source of the information is, usually the package label. Companies round off calorie content and macro values. An item with 4.4g of fat, 12.3g of protein, and 20.2g of carb, of which 8g is fiber, might be labeled as 160 calories, 4g fat, 12g protein, 20g carbs. If you add that up you get 164 calories. Some labels have numbers that don't seem to add up at all for me, so I figure they must determine macro content and calorie content in two different ways (for instance, they measure the calorie content in a calorimeter but calculate macros from ingredients added during production).

But regardless, MFP doesn't process the macro contents into a calorie value. Your daily totals are just totals added up from the respective columns.

Sarauk2sf

The other thing that can impact the math is fiber. Fiber, while counted in carbs, actually has about 2.5 cals per gram (depending on the type).

Ok, this is good to know. I recently started paying more attention to my fibre, and have upped it considerably. Last night, when planning today's food, I noticed that my macros were all bang-on or slightly over, yet I was below my calorie goal. This left me scratching my head. How should one account for this in their calories for the day, then?

As it only impacts carbs, and carbs are variable, I would just go by calories as it should not make that much of a difference due to inherent estimation errors anyway. It is just one of those annoying things that make the math not quite work when looking at daily totals.

pcain123

Greatly appreciated this post. I have just started with calculating and following macros. I ate a Quest bar today and wondered why my calorie count was still 100 calories under when all my macros showed up as 0. I also didn't know whether to go ahead and eat the calories or not--thanks again.

bumblebums

The other thing that can impact the math is fiber. Fiber, while counted in carbs, actually has about 2.5 cals per gram (depending on the type).

Ok, this is good to know. I recently started paying more attention to my fibre, and have upped it considerably. Last night, when planning today's food, I noticed that my macros were all bang-on or slightly over, yet I was below my calorie goal. This left me scratching my head. How should one account for this in their calories for the day, then?

Solution: alcohol!

cmeiron

The other thing that can impact the math is fiber. Fiber, while counted in carbs, actually has about 2.5 cals per gram (depending on the type).

Ok, this is good to know. I recently started paying more attention to my fibre, and have upped it considerably. Last night, when planning today's food, I noticed that my macros were all bang-on or slightly over, yet I was below my calorie goal. This left me scratching my head. How should one account for this in their calories for the day, then?

Solution: alcohol!

^ we have a winner!