Macronutrients compliance between foods labels and marketing package content values


Background: Nutrient labeling raises consumers’ awareness of nutritional values of foods. However, uncertainties with regard to amluracy of nutrition facts’ labels have recently increased. Objective: The objective of this study is to determine the compliance between information presented in food labeling of widely consumed foods and their true values. Materials and Methods: This study investigated 24 types of foods including dairy, meat, and protein rich foods, snacks, dressings and tomato paste, and pasta. In total, 1764 experiments were conducted. The levels of fat, carbohydrate, and protein were measured using Folch method, Fehling’s solution, and Kjeldahl device, respectively. The data were then analyzed using Spearman correlation coefficient and Wilcoxon test. Results: The amount of fat, carbohydrate, and protein content in 67.8%, 48.4%, and 38.5% of analyzed foods was different from their nutrition fact labels. The fat content on nutrition facts label of dressings was lower than their analyzed values (10.15 ± 15.87 vs. 11.40 ± 21.44 g, P = 0.001). In total, the fat content on food labels was significantly different from analyzed values (15.54 ± 13.02 vs. 12.60 ± 10.77 g, P = 0.001). The carbohydrate content on food labels of meat and protein foods was less than their analyzed values (5.49 ± 3.24 vs. 6.88 ± 4.47 g, P = 0.001). Conclusion: The study showed a significant difference between laboratory analyzed values and food labels nutrition facts which may have misleading effects on foods choice of customers. In general, lack of amluracy in labeling nutritional value of foods and providing inamlurate information might lead to public unhealthy eating.

Keywords: Carbohydrate, fat, food analysis, nutrition fact label, protein

How to cite this article:
Pasdar Y, Darbnadi M, Azandaryani AH, Sharafi H. Macronutrients compliance between foods labels and marketing package content values. Ann Trop Med Public Health 2017;10:999-1003


How to cite this URL:
Pasdar Y, Darbnadi M, Azandaryani AH, Sharafi H. Macronutrients compliance between foods labels and marketing package content values. Ann Trop Med Public Health [serial online] 2017 [cited 2020 Aug 10];10:999-1003. Available from:



In many parts of the world, food industries and distributors, consumers, and governments are reexamining the provision of nutritional information on food packages.[1] The nutrition label is an important vehicle through which food manufacturers can communicate essential information about the nutritional value and composition of their product. Consumers are interested in the nutritional quality of food products and need transparent nutritional information about their purchases.[2]

It is important that the provided nutritional information be appropriate and understandable to the consumer and that it has a positive impact on food choice behaviors. Potentially, food labeling is a valuable tool to help consumers make informed decisions about their diet to improve health and prevent chronic diseases.[3] Nutrition labels are perceived as highly credible sources of information and many consumers use nutrition labels to guide their selection of food products.[1]

The USDA’s 2010 Dietary Guidelines Advise Americans to control total caloric intake and reduce sodium, saturated fat, transfat, cholesterol, and added sugar consumption.[4] The provision of clear and amlurate nutrition information is one important way to help consumers adhere to these guidelines and make informed choices. Nutrition labels on food packaging and restaurant menus offer one of the best ways to disseminate and make salient such information at the point of purchase, when it is arguably most likely to influence purchasing behavior. In addition, required disclosure of nutrition information can incentivize food manufacturers to improve the nutrient profile of their products.[5]

The results of a study conducted in Brazil to determine the reliability of food labels showed that more than half of the drinks were rejected due to the great difference between the values reported on labels and their laboratory-measured values. Moreover, obesity-related nutritional content showed the highest discrepancy with true values.[6] A study in the United States evaluated the caffeine content of drinks and the results showed that the amounts were different from their true values.[7] Some studies have reported cases of food fraud in Poland such as adding unpermitted colors to foods such as turmeric, curry, and palm oil. Such frauds in providing amlurate information to people might endanger their health or cause poisoning.[8],[9]

Nutrition facts’ labels are customers’ right for obtaining nutrition information and amlessing the quality and safety parameters of foods. Nutrition information on food labels should be useful and understandable for consumers and provide the truth because it might influence individual’s food choice.[1],[6],[10]

Macronutrients such as fat, protein, and carbohydrate play important roles in an individual’s diet, so their amount is taken into consideration by people intending to lose or gain weight, or those who should comply with special diets for different illnesses.


In view of the importance of these macronutrients, the present study intended to define compliance between the amount of protein, carbohydrate, and fat reported on the nutrition facts labels of these foods and their true values.

Materials and Methods

The following chemicals used in the present study were procured from Merck Company: sodium hydroxide (NaOH), chloroform (CHCl3), methanol, n-hexane, BF3, butylated hydroxytoluene (BHT), FeCNK, zinc acetate, Kjeldahl tablets, methyl blue, and filter paper.

The present cross-sectional study evaluated 24 types of commonly consumed foods which fell into five groups of dairies (yogurt, milk, cheese, mozzarella, ice cream), meat and high-protein foods (cold cut, sausage, burger, processed meat, processed chicken, cocktail sausage, tuna fish, minced meat), snacks (potato chips, puffs, cake, muffins, biscuits, wafer cookies, mini filled cake, non-alcoholic beer, juice), dressings and tomato paste (tomato paste, ketchup, mayonnaise), pasta (simple spaghetti, shaped pasta).

Four different brands of each types of food were selected from shops across the city and samples were transferred and kept in the laboratory under favorable temperature and moisture condition. Three samples of each kind of food were prepared and laboratory tests were carried out twice. In total, 1764 laboratory tests were performed.

The amounts of protein, carbohydrate, and fat were measured using standard methods and the results were compared with the values reported on food labels.

Protein measurement using Kjeldahl analyzer

Kjeldahl analyzer can test six samples simultaneously. Thus foods with similar protein content were selected in every round of tests and one gram of each food was added to either one or two Kjeldahl tablets (for low-protein and high-protein foods, respectively), followed by adding 25 concentrated sulfuric acid. The solution was placed in digesting device for 90 min. Then, 50 ml of distilled water was added to each sample. One Erlenmeyer flask was prepared for each sample, and 50 ml of boric acid 2% and 2–3 drops of methyl bromocresol were added to the samples. These flasks were placed inside Kjeldahl device. The resulting solution was tittered with HCl and the amount of consumed HCl was substituted into the following formula to measure protein concentration:

B equals the amount of tested sample in the study. A is the amount of hydrochloric acid used in titration. The conversion ratio of nitrogen gas to nitrogen liquid was 6.25 while 1 ml of 0.1 normal hydrochloric acid equals 1.4 mg nitrogen. From the equation, the X equal the percentage of protein in samples.[11]

Quantitative determination of carbohydrates

In the study, the amount of carbohydrates measured by Fehling methods. The measurement procedure started with weighting 5 g of foods. Then, 50 ml of 15% HCl was added and the mixture was heated for 90 min at 100°C. Following hydrolysis after 90 min, NaOH was added to neutralize the solution. Then, 4 ml of FeCNK and 4 ml of zinc acetate were added and NaOH was once again added drop by drop until the pH reached 8. Distilled water was added to reach the volume of sample to 200 ml; finally, the solution was passed through a filter paper.

The filtered solution, with 5 ml of Fehling A and 5 ml of Fehling B and 200 ml of distilled water, was heated on a Bunsen burner till boiling point. Then, 2–3 drops of methylene blue were added to the solution and the filtered solution was tittered while boiling and the volume of the titrated substance was recorded. The carbohydrate content was measured using the following formula:

Where a is the amount of Fehling titrated substance and 5 is the amount of sample (g) taken for measuring the levels of carbohydrate.[12]

Fat measurement through Folch method

The fat content was measured by extraction and then weighing the samples using sensitive four-digit precision scale. Initially, 10 ml of chloroform-methanol solution 2:1 was added to one gram of the sample. Then, 0.01% volume weight BHT powder was added and the test tube was shaken for 5 min. The mixture was then filtered and transferred to the test tube while specific ratio of distilled water was added. The organic phase of the two-phase solution was separated and the solution was centrifuged three times at 4000 rpm for 2 min to increase the rate of extraction. The remaining solution was dried at 50°C with nitrogen. The dried samples were weighed with test tubes and were then dissolved in 1 ml n-hexane. The empty test tubes were also weighed and the difference of measure weight showed the fat content in grams.[13],[14]

The results of the study were analyzed using SPSS 19 (SPSS Inc., Chicago, Delaware). The mean (± standard deviation) was used to describe the normally distributed data while median was used for nonnormal data. Kolmogorov–Smirnov test was used to assess data normality. The data were then interpreted using Wilcoxon test (with confidence interval of P < 0.05).


This study measured the protein, fat, and carbohydrate content of 24 types of most widely consumed foods from different brands. The foods fell into five groups of dairy, meat, and protein rich foods, snacks, dressings and tomato paste, and pasta.

The nutrition labels on meat and high-protein foods such as sausage, cold cut, burger, and ham had reported the amount of carbohydrate less than the analyzed values (5.49 ± 3.24 vs. 6.88 ± 4.47 g, P = 0.001). While the true value and the reported value of carbohydrate were not significantly different in other types of foods including dairies, snacks, pasta, dressings, and tomato paste. The median value of carbohydrate in snacks was reported as 54 on labels and 50.85 in laboratory tests [Figure 1].

Figure 1: Comparing carbohydrates reported on nutrition fact label and laboratory-measured values

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The mean amounts of protein on nutrition labels of dairies were less than laboratory-measured amounts (7.91 ± 6.16 vs. 7.64 ± 7.13 g) which was not significantly different (P = 0.734). The median amount of protein in pasta reported on nutrition labels (11.06 ± 1.35 g) and in laboratory test (12.16 ± 0.94 g) was significantly different (P = 0.027) [Figure 2].

Figure 2: Comparing protein reported on nutrition fact label and laboratory-measured values

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The nutrition facts of dairies were significantly higher than analyzed values (P = 0.001). The mean value of fat content in snacks was reported as 19.66 ± 11.98 g while it was measured as 13.62 ± 8.88 g in laboratory tests, so the difference was statistically significant (P = 0.001). The fat content reported on nutrition labels of dressings and paste was far less than the true value (10.15 ± 15.87 vs. 11.40 ± 21.44 g, P = 0.001). In general, the levels of fat reported on nutrition facts labels were significantly different from their analyzed value (15.54 ± 13.02 vs. 12.60 ± 10.77 g, P = 0.001) [Figure 3].

Figure 3: Comparing fat reported on nutrition fact label and laboratory-measured values

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The amount of fat in 67.8% of evaluated foods was either less or greater than true values. The true values of carbohydrate content and protein content in 48.4% and 38.5% of foods were different from their labels.


This study showed the amount of fat in 67.8%, carbohydrate content and protein content in 48.4% and 38.5% of foods were different from their labels. In the study, fat, protein, and carbohydrate content presented on food labels were significantly different from their laboratory-measured true values. The fat content in food labels of all evaluated foods, especially the dressings, was greatly less that the true values. The carbohydrate content presented on labels was also clearly different from their true values as the carbohydrate content in nutrition facts of meat and high protein foods, such as sausage, cold cut, burger, and ham, was less than true values. The laboratory-measured protein values were not significantly different from values reported on labels though protein content on labels of pasta was less that the measured one.

The measurement of protein, fat, and carbohydrate in the human meals and investigation of their effect on body are so important. Raben et al. measured the amount of energy intake from food by focused on protein, fat, and carbohydrate and alcohol. Hence, it should be important to measure these values in the consumed food.[15],[16] A study conducted in United State evaluated the amluracy of nutrition facts label of snacks. The results indicated that the calories in widely used high-calorie snacks were higher than the value on their labels. Moreover, the true carbohydrate content of macronutrients was greater than their values on food labels.[17]

The study conducted by Pantazopoulos et al. in Canada tested more than 380 types of sweets, biscuits, and various types of frozen foods in laboratories. The results showed that there was no statistically significant difference between the labels and laboratory-measured values. Thus, Canadians can trust food labels for having a conscious and mindful eating diet.[18] Another study in Brazil evaluated the reliability of food labels in 153 samples from 84 food brands. Amlording to the law, 20% difference is currently amlepted between permitted amounts and the true amounts for statistical calculations. More than half of the drinks were rejected in view of the great difference between the values of labels and laboratory measured. The presence of obesity-related nutrients scored the highest level of noncompliance.[6]

The present study results revealed that nutrition facts expressed in labels were different from their true values. One reason is that standard food labeling methods are not employed in Iran, and reference books and nutrition charts are used for this purpose, which are not updated. Another reason might be the changing formulas and measurement methods used by inexperienced technicians in factories. Furthermore, it is highly possible that these facts are taken from a one-time measurement and used for the future production batches.

Literature review on compliance between values reported in food labels and values obtained from laboratory measurements in Iran confirms inamluracy of nutrition facts labels, and that food labels of a remarkable number of evaluated foods were significantly different from their true values. The advantage of the present study was the large sample size and evaluating significant numbers of widely consumed foods across the city.


The study showed a significant difference between laboratory-analyzed values and food labels nutrition facts which may have misleading effects on foods choice of customers. In general, lack of amluracy in labeling nutritional value of foods and providing inamlurate information might lead to public unhealthy eating.


We gratefully acknowledge the Research Council of Kermanshah University of Medical Sciences (Grant Number: 91283) for the financial support and Research Center for Environmental Determinants of Health in School of Health.

Financial support and sponsorship

The study was supported by the Research Deputy of University of Medical Sciences, Kermanshah, Iran.

Conflicts of interest

There are no conflicts of interest.



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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ATMPH.ATMPH_309_17


[Figure 1], [Figure 2], [Figure 3]

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