Which are the most common mistakes people make when using a food tracker such as MyFitnessPal regarding making entries and utilizing these? How can we avoid them?

EDIT: if you can think of more pitfalls that would be common in using a food tracker, feel free to add as a comment or answer and I will upvote accordingly.

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  • Some informations from an analytic chemist (Europe): There are different labeling systems/informations. The Big 7, which is Fats (measured), incl. saturated fats (measured), Protein (calculated from the Nitrogen content), Minerals (the amount of ash after burning), salt (calculated from Na determination ), Carbohdrates (calculated from Fat, Protein, Ash and Water content), incl. sugars (measured partially), and Energy (calculated). Big 8 has also the fibers (undigestibles, which are then substracted from sugars). So carbs are normally only calculated "what`s left) and Protein is estimated. – Julian May 17 '16 at 13:21
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    This is useful. But is this within the site charter? – Sean Duggan May 17 '16 at 13:22
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    @SeanDuggan Kind of indirectly. Nutrition is gonna be a part of a successful training regime, lots of folks will use MFP (or it will be suggested they use it) and they're gonna run into the mentioned issues. So this might be useful for them. It's kind of a meta-subject that could be pointed towards. If you feel it's better at home in the health SE it could be moved provided it's not off-topic there. – G_H May 17 '16 at 13:32
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    @G_H: Honestly, I think that Health also has played hot-potato with the issue of nutrition questions. – Sean Duggan May 17 '16 at 14:23
  • All sites have played hot potato with nutrition. Nutrition was in scope here originally, then it was decided it was only allowable if it related to a fitness regimen and how it would affect it. This is soliciting opinions, which isn't on topic on almost any SE site I can think of. There is a nutrition proposal on area 51 I would encourage people to follow. – JohnP May 18 '16 at 20:24

Making and correcting entries

General considerations

Where possible, utilize grams. Metric units are easier for conversions and calculating serving sizes. Furthermore, MFP lists nutrients in grams and milligrams, so basing yourself on grams just gives an overall better picture of what you're getting.

If the values for a certain nutrient are unknown, leave it blank. I see people filling these in with 0's, but the message you're sending is different. If a food lists fats and tells you how many of those are saturated, that doesn't tell you how many are poly- and monounsaturated. Stating these are 0 is probably incorrect. Leaving the fields blank says "I don't know".

Go with the information on a food label if there is any. Even for whole foods, where generic entries may be found, it pays to use specific values for a specific product of a brand if these are listed on the packaging. If information is lacking, sometimes a brand's website can provide it. Don't go taking values out of other user-submitted entries on other sites and applications such as FatSecret, because these are just as vulnerable to incorrect information. This would only make things worse, because now people see these values in multiple places and assume they must be correct. For whole foods such as fruits, vegetables, meat, fish and more, use information from well-estabished databases such as the USDA. An excellent reference database is that of http://nutritiondata.self.com/, which provides info for various serving sizes, always including 100 grams (see further) and plenty of other info such as micronutrients.

Finally, note that sometimes for the same brand and product, values can be different per country based on local production or legislation. If so, it may be best to make a separate entry with the country mentioned after the brand name or product name.

Serving size & servings per container

If possible, provide a serving size of 100 grams. This is the easiest to work with. If a different unit is used, always prefer weight units. I see things such as "1 cup". This is simply not accurate. For a liquid it is hard to measure exactly one cup, since it may be filled until the surface is slightly above the cup edge or right below. For flour, 1 cup can be very different depending on how finely it was milled and how densely you pack the cup. This can make for a difference of up to serveral dozens of kilocalories, which may not seem much but adds up over the days and weeks. Serving sizes of "1 slice" for things like bread are completely useless because there can be too much variation. There's no proper standards there, and even if there were it is unlikely a user cared to find out. If they did, they'd have bothered to use weight. If a serving size is given on a label using a different measure (for example, 125 grams) it's still better to do the conversion for each nutrient and list the 100 gram values. You just multiply everything by 100 g/x g where x is the listed serving in grams. So if for example values are given for 125 grams, just divide everything by 1.25. Your computer's calculator app is your friend. I'll state the reason for this below.

Servings per container can be given as stated on the container, but I'd suggest just keeping this at 1. You may find a pasta sauce that comes in containers of 250 grams and 500 grams. If someone can't figure out that 250 grams is 2.5 servings of 100 grams they are beyond your help anyway. Besides, these aren't always accurate. I frequently buy jars of 500 grams of yoghurt but when measuring I manage to scrape out at most 490 grams because some always stays behind in the container and some water content may have evaporated. When getting oven baguettes I've found that they list the weight for one as 125 grams but in practice they end up weighing a little more. A company would rather give you a bit too much than risk getting sued for not providing what they sell. So don't just go by what's on the packaging, weigh your food. This is the reason why providing values for 100 grams is preferable, because it lets you state the measured serving yourself without too much math involved.


These are kilocalories. The biggest mistake here is people stating a certain serving size, but then using the kilocalorie value from a different serving size. For example, they state serving size is 100 grams (good) but then mistakenly read the kilocalorie value on a label that gives it for, say, 70 grams (bad, you've now underestimated your calorie intake). Another thing to look out for is kilojoules. Some labels state values in both kilocalories and kilojoules. Don't mix these up. If a label provides only kilojoules (yes, I've had this happen) multiply that value by 0.239 to get the kilocalorie value.


What you'll usually find on a label is "fats" and then "of which saturated". If no information is provided regarding exactly how much is poly- and monounsaturated, or trans fats, don't fill in anything for those fields. Stick to fats (most important) and saturated (may be important for some people), only providing the other types if they are properly listed.


Pay attention to the fact that this field is listed in milligrams. Since there's no distinction between various types of cholesterol, and the relation between dietary and blood cholesterol has come under scrutiny, I'll admit I usually don't pay much attention to this field.


Important note: one of the most common sources of mistakes

Sodium is a chemical element with chemical notation Na (from "natrium"). Salt is a molecule consisting of a sodium cation (Na+) and chloride anion (Cl-). Its chemical notation is NaCl. The sodium cation makes up about 40% of the molecular weight. This is not exact but close enough for all practical purposes.

Sodium and salt are not synonyms. Salt will often be the main source of sodium in food, but it is not always the only source. What you're supposed to provide in MFP is the sodium content. Whether a label lists sodium or salt varies, and what it is obliged to list can depend on jurisdiction. It can be different in various countries.

If a label lists sodium content, use that. If a label lists only salt content, multiply it with 0.4 to get sodium content. Note that if sodium content is listed, you'll know exactly how much sodium is in there, but if salt is listed you've only got a lower limit for the sodium. There could be other sources of sodium than the salt. But if it's all you have to go on, then it's better than nothing. Again and again I see entries where the salt content on the label is listed as sodium, which will give a gross overestimate. I'll repeat, sodium is 40% of salt.

Also keep in mind that sodium is listed in milligrams, not grams. So if you are given sodium content in grams, multiply by 1000 to get the the milligrams. If you get salt content in grams, multiply by 400 to get sodium in milligrams (this is effectively x 1000 x 0.4). I've seen people just literally copying what's on a label. So a label stated "1.9 grams salt" and they put 1.9 in the sodium field, meaning they failed to both convert to milligrams AND realize sodium and salt aren't the same thing.

I'll give an example: if the label says 1.9 grams salt, that means it has 1900 milligrams of salt, and that in turn means you get 0.4 x 1900 milligrams of sodium, = 760 mg. THAT is what goes into the field in your MFP entry.

Sodium intake is important for some people so pay attention to getting this right for their sake.


Important note: one of the most common sources of mistakes

Carbs consist of sugars, fiber and starches, amongst possibly some other things. You'll usually find entries for total carbs, sugars and fiber on a food label. Now here's one of the main sources of confusion: this is different in the US and Europe (and around the world). A US label would look like this:

  • Total carbs: x grams
    • of which sugars: y grams
    • of which fiber: z grams

A label in Europe (or at least in Belgium, where I live) would look like this:

  • Total carbs: x grams
    • of which sugars: y grams
  • Fiber: z grams

There is a subtle but important difference. In the US, fiber is counted towards the total carbohydrates. In Europe, total carbs are typically listed without the fiber, and fiber is listed separately instead. MyFitnessPal uses the US standard. So if you're outside of the US, interpret the label correctly. This means you'd have to add the fiber content to the total carbs. Here's an example of what you may see on a European label:

  • Total carbs: 10 grams
    • of which sugars: 5 grams
  • Fiber: 3 grams

This means there's 10 grams of carbs consisting of (5 grams of) sugar and probably some starches, and on top of that there's 3 grams of fiber. In MFP your entry now needs to look like this:

  • Total Carbs: 13 grams
    • Dietary Fiber: 3 grams
    • Sugars: 5 grams

If you see some entry where the sugars and fiber add up to more than the total carbs, that's a red flag. This is something I have to fix on pretty much 95% of all entries I find and, along with the sodium, is the most common mistake. This is important for people on low-carb or keto diets. Dietary fiber doesn't (or only partially) count towards their carb intake. So they'd look at their total carbs per day and then subtract the fiber. If the fiber wasn't accounted for in total carbs to begin with, they're getting less carbs than necessary. Not so nice when you're already seriously carb restricted and you believe you're still eating too much of them.


For this, the general considerations just apply. I don't tend to see as much mistakes with this as with sodium and carbs or calories and serving sizes.


There are given in MFP as a percentage of daily recommended intake. But note that confusion may arise here. For some things there's a daily recommendation, while for others there's a daily allowance that you should try not to go over. Don't mistake one for the other. Also, this is different for women, men, adults and children, and can depend on body mass. I usually leave these blank unless they're precisely stated on a label. For whole foods you can consult the aforementioned Nutritiondata. Mind that some labels are sneaky (for example, some fortified breakfast cereals) and will give values for a certain weight for one thing and then values for a serving size for another (with milk included sometimes for cereals).

Correct use

So how can you use MFP correctly given the above? First of all, if you notice incorrect entries, correct them. You're doing yourself and others a favor. Use the comment field to specify what you've changed and why. I've got a couple of very typical lines. For example: "Adjusted sodium content, salt content was given." "Added fiber to total carbs." If there's an entry that can be corrected, prefer correcting that instead of making a new one yourself. This would only make it more confusing and harder for people to find accurate entries.

If adding a new food to the database, share it with other members. The checkbox is off by default. If you follow the above guidelines and make complete, accurate entries, they are an asset to the database and community. Choose names that are as complete as possible. Say you have a brand and they provide carrots, specify if they're frozen or not, and if they're whole or sliced. Try to go with exactly what's on the packaging but don't be afraid to add some qualifiers yourself, it'll help people search.

Weigh everything. Weight listed on packages isn't always entirely accurate. Get a kitchen scale. A digital one with at least 1 gram resolution is preferable. It doesn't have to be very expensive, just invest in something that looks durable and is accurate enough. A flat scale without a bowl is best. A bowl may seem useful but some larger foodstuffs can be inconvenient to weigh with it. If you want to put the food in a container, you can first place it on the scale, then tare the weight so it reads 0 and then add the food to get the net value. Most digital scales let you do this easily, which makes them more convenient than analog ones (which can also be hard to read with enough precision).

Should you weigh foods raw or cooked? This is a difficult one. Raw is usually best; it's less hassle to weigh something before you've cooked it (and want to start eating it) and it will usually be more accurate. Entries for cooked foods may be different from what you have depending on how long it has been cooked and how much fat and moisture has come out of it. Take a chicken for example: when roasting, water will evaporate and fat drippings will come out. The very same chicken may end up quite differently depending on how long it has been roasted and how moist or dry the meat has become. A tactic could be to use entries for raw poultry, weigh it raw, then after eating weigh the bones to find out how much net raw chicken you've consumed. But even there you'll find some variation, because the bones will have lost some weight depending on cooking time. When weighing raw it can in this way sometimes be easy to slightly overestimate calories. If you are trying to lose weight, overestimates are better than underestimates. When trying to gain weight, it's the other way around. If you're on a serious bulk all that fat that's dripped out of your chicken or bacon and that you may have counted in your raw entry would be lost, so, eh... drink it, or use it in soup stock or (for bacon) use it as lard.

This concludes my advice on the use of MyFitnessPal which is based on more than a year of diligent tracking, studying many sources regarding nutrition and trying to be as accurate in correcting and making entries as possible.

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  • Excellent resource! – Tim Malone May 17 '16 at 22:54

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