MyFitnessPal cant count...

RonRoff
RonRoff Posts: 175 Member
edited November 25 in Food and Nutrition
Ok, consider these facts:

1 proteine = 4kcal
1 fat = 9kcal
1 carb = 4kcal

My goals are 2250kcal, based on 141g carbs, 88g fat, 225g proteins.

Adding it all up:

141g carbs * 4 = 564kcal
88g fat * 9 = 792kcal
225g proteines * 4 = 900kcal
Total kcal: 900+792+564 = 2256kcal.

So far so good right, the difference of 6kcal on my total is acceptable.

Now today, i was planning my food and it told me i had 121kcal to spare.
I took a brief look on my intake, i have 4 carbs left, went over 9 fats and had 0 proteines left...

Sooooo, my intake today should be

136g carbs (i know right, this is also 1 off) * 4 = 544kcal
97g fat * 9 = 873kcal
225g proteines * 4 = 900kcal
Gives me a grand total of 2317kcal

Meaning i already went OVER for 67kcal, let alone that it tells me i can eat 121kcal MORE....
If i just do that, i end up 200kcal over.

I've been using MFP since february, and i'm wondering how many extra cals i took, by trusting the nice green figures in the bottom.

So be wary just trusting the totals of MFP, because appearantly, it isn't something you can trust.

// A frustrated user of MFP

Replies

  • yarwell
    yarwell Posts: 10,477 Member
    Rounding ? If the 97g of fat is 96.5 for example.

    I think it adds up the meal totals, and they are rounded, rather than adding up the totals for the day separately.

    Who needs 225g of protein(e)s anyway ?
  • blankiefinder
    blankiefinder Posts: 3,599 Member
    I thought that fat was 1g=8 calories? Which would change your grand total to 2220.

    As to the rest of the difference, is it giving you automatic credit for steps or something? Plus some of it might be it rounding up or down without you seeing. Regardless, I wouldn't sweat a difference of less than 100 calories since there will always be some variation, even to the actual calories in a food item. The actual calorie count of a packaged food is allowed a certain margin of error in it's calorie counts, so no count will ever be so precise that it will be perfect anyway.

    Have you been losing slower than expected, and if so, how much slower?
  • RonRoff
    RonRoff Posts: 175 Member
    edited October 2015
    @Yarwell I'm eating an elevated amount of proteins (sorry not native english), because i'm recovering from a nasty knee injury. I'm at 2.1g per kg bodyweight (as i'm 104kg). Normally i eat closer to 180g proteines.

    @Blankiefinder It's definitely 9kcal per fat. I'm losing just fine, because i'm using TDEE as a calculation method. I book all my exercise as 1kcal burns, creating a larger deficit than MyFitnessPal is actually aware of. But it's frustrating to become aware of the fact that the tool that you use for measuring, has some problems with calculating grand totals :wink:

    On a sidenote, i'm a personal trainer and weight consultant in real life, and MFP is my goto tool for getting my customers up to measuring levels with food. So that makes it extra frustrating, because i really dont want to start looking for something else (in a matter of fact, i definitely wont because i absolutely love this interface).
  • yarwell
    yarwell Posts: 10,477 Member
    9,4,4 is an approximation anyway. With American carbs including fiber I'm not sure about multiplying them by 4, let alone the 3.8 that might suit sugars.
  • blankiefinder
    blankiefinder Posts: 3,599 Member
    RonRoff wrote: »
    @Yarwell I'm eating an elevated amount of proteins (sorry not native english), because i'm recovering from a nasty knee injury. I'm at 2.1g per kg bodyweight (as i'm 104kg). Normally i eat closer to 180g proteines. I'm a

    @Blankiefinder It's definitely 9kcal per fat. I'm losing just fine, because i'm using TDEE as a calculation method. I book all my exercise as 1kcal burns, creating a larger deficit than MyFitnessPal is actually aware of. But it's frustrating to become aware of the fact that the tool that you use for measuring, has some problems with calculating grand totals :wink:

    On a sidenote, i'm a personal trainer and weight consultant in real life, and MFP is my goto tool for getting my customers up to measuring levels with food. So that makes it extra frustrating, because i really dont want to start looking for something else (in a matter of fact, i definitely wont because i absolutely love this interface).

    Ah yes, I shouldn't try to think when it's 2 AM and I'm sleep deprived. Regardless, my guess is that it's from rounding and such, as it would be unusual for a computer to make a math error, more common that the error would come from calculations we can't see such as hidden fractions.
  • RonRoff
    RonRoff Posts: 175 Member
    edited October 2015
    @yarwell They are in close proximity of 4kcal, and i can fully accept that it deviates a little bit from the calculation ofcourse. But according to my calculations in the first post, MFP is using the 9,4,4 totals, since when i add everything up, it is correct. Just the live calculation based on food isnt measuring properly.

    @blankiefinder yeah i'm 100% sure that this is also one of the reasons that causes differences, and one cannot expect more from a tool like this, also because it's user entered data AND a lot of fractions are involved.

    The main frustrating thing is, when you see i have 4 carbs left to spare, and went 9 fat over, but yet MFP thinks i should eat 121kcal more. even if i went 0 fat over, that value should be to eat about 16kcal more.
  • yarwell
    yarwell Posts: 10,477 Member
    edited October 2015
    MFP does use 9,4,4 indeed. My point was that those aren't the actual calorific values of every food so there might be a 5% approximation in there already - in which case a 5% variation in rounding may not be too much to worry about.

    I'll cross check one of my days and see how it looks....

    Diary on screen -
    xlnj05j3b5s5.png

    printed summary of day -
    8g3euuw96vrk.png
  • RonRoff
    RonRoff Posts: 175 Member
    @yarwell for you it seems to be ok so far, maybe it has something to do when you go over your daily intake, ofcourse my totals are 2250kcal so, that was a bit less than 3 times as large as yours, maybe the difference becomes larger as the kcal intake grows
  • yarwell
    yarwell Posts: 10,477 Member
    RonRoff wrote: »
    @yarwell for you it seems to be ok so far, maybe it has something to do when you go over your daily intake, ofcourse my totals are 2250kcal so, that was a bit less than 3 times as large as yours, maybe the difference becomes larger as the kcal intake grows

    There are two discrepancies each of a gram. I suspect more meals = more potential rounding errors.
  • Yi5hedr3
    Yi5hedr3 Posts: 2,696 Member
    Yes - I have noticed similar issues with various totals. Example, when you produce a report to print, totals are always different. Very frustrating.
  • DeguelloTex
    DeguelloTex Posts: 6,652 Member
    edited October 2015
    yarwell wrote: »
    Who needs 225g of protein(e)s anyway ?
    I do.

    I think MFP can count. Small discrepancies are probably due to rounding. Larger ones are usually due to mistakes in the database entries.
  • rileysowner
    rileysowner Posts: 8,336 Member
    It would come down to rounding. Some days the rounding up and rounding down will more or less even out. Other days, the rounding up will prevail and give numbers for macronutrients that don't fit at all with the calories. Other days the rounding down will prevail with the same result. Add to this potential database issues, say a person hitting the wrong number when typing in something, and you have the answer to why things don't match up.

    When it comes down to it there will be natural variations in the makeup of food that means that numbers are always a near approximation rather than a precise measure.
  • RonRoff
    RonRoff Posts: 175 Member
    @HappyCampr1 thanks for the tip, i changed that one to another "baked egg" entry and the difference became a lot smaller, so that means, it probably acumulates the different types of fats internally, instead of using the grand total (atleast thats what i expect). I think MFP is doing the same with carbs, which can explain the differences i get.
  • SingRunTing
    SingRunTing Posts: 2,604 Member
    Combination of rounding and database entries aren't always 100% correct.
  • rgarciajr11
    rgarciajr11 Posts: 2 Member
    yarwell wrote: »
    Rounding ? If the 97g of fat is 96.5 for example.

    I think it adds up the meal totals, and they are rounded, rather than adding up the totals for the day separately.

    Who needs 225g of protein(e)s anyway ?

    I need 225 grams of protein a day.
    I'm on a 2kcal cal deficient plan. I need 45% cals from protein and yesterday it said my goal was 335 grams for goals.
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