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Validation Information: 24h Recall (Food Photography)

Lazarte 2012

Validation of digital photographs, as a tool in 24-h recall, for the improvement of dietary assessment among rural populations in developing countries

Background. Improvement of traditional methods for dietary assessment is necessary, especially in rural areas where it is more difficult to succeed with self-reporting methods. This study presents and validates a method for improving accuracy when measuring food and nutrient intake of individuals in rural areas. It is called the “Food photography 24-h recall method” (FP 24-hR) and is a modified 24-h recall with the addition of a digital food photography record and a photo atlas.

Methods. The study was carried out in a rural area in the tropical region of Bolivia; 45 women participated. Validation of the method was made by comparing it with a reference method, the Weighed Food Record (WFR). During the FP 24-hR, digital photographs were taken by the subjects of all food consumed during a day and a 24-h recall questionnaire was conducted by an interviewer. An estimate of the amount of food consumed was made using a photo atlas and the photographs taken by the subjects. For validation, comparison was made between the calculations, by both methods, of the levels of food, and nutrient, intake.

Results. The comparison was made in 10 food categories; most of which were somewhat underestimated from −2.3% (cassava) to −6.8% (rice), except for beverages (+1.6%) and leafy vegetables (+8.7%), which were overestimated. Spearman’s correlation coefficients were highly significant (r from 0.75 for eggs to 0.98 for potato and cassava). Nutrient intakes calculated with data from both methods showed small differences from -0.90% (vitamin C) to -5.98% (fat). Although all nutrients were somewhat underestimated, Pearsons coefficients are high (>0.93 for all) and statistically significant. Bland Altman analysis showed that differences between both methods were random and did not exhibit any systematic bias over levels of food and nutrient intake, with acceptable 95% limits of agreement.

Conclusion. The FP 24-hR exhibits acceptable differences when compared with a WFR, digital photos are useful as a memory aid for the subjects during 24-h recall and as an estimation tool. The method is suitable for assessing dietary intake among rural populations in developing countries.

Web Link

Validation Information

Year of Publication

Tool Information

Dietary Exposure Measured
Full Nutrient, Food Groups
Tool Type
24 Hour Recall
Timeframe Tool Measures info
1 day
Portion Size Measures info
Photographs and photo atlas were used to aid portion size estimation
Reporting Method info
Format info
Supplements Measured
Administration Method info
Interview administered

Study Information

Study Location
Eterzazma, Bolivia
Associated Nutrient Database
USDA National Nutrient Data Base
Comparator Validated Against
Weighed Food Diary


Sample Size
Age of Population

Range: 20-52 years; Mean (SD): 35 (8.6) years

Female Only
Other Notable Characteristics
The subjects were from the rural region, Eterazama, Cochabamba, Bolivia. The 24-h recall was conducted by trained dietitians.

Total number of nutrients validated: 15 info

Not all of the nutrients validated in the validation studies are included in the table below, as statistical data was only selected to be displayed for a number of nutrients, this included:

  • Energy
  • Fat
  • Saturated Fat
  • Mono-unsaturated Fat
  • Poly-unsaturated Fat
  • Carbohydrates
  • Protein
  • Sugar
  • Non‐starch polysaccharides(NSP)
  • Sodium
  • Calcium
  • Iron
  • Zinc
  • Retinol
  • Folate
  • Folic Acid
  • Vitamin B12
  • Vitamin C
  • Fruit & Vegetables
  • Urinary Nitrogen

To find information on the other validated nutrients please read the validation study.

  • Energy
  • Macronutrients: 4
  • Micronutrients: 11
Comparator Lifestage Sex Nutrient Measured info Mean Difference Standard Deviation info Correlation Coefficient info Cohen's Kappa Coefficient Percentage Agreement Percentage Agreement Categories info Lower Limits of Agreement Upper Limits of Agreement
Weighed Food Diary Adults Female Only Energy (kcal) -56.9 0.99 (P) -163.2 49.2
Energy (kJ) -238 0.99 (P) -683 206
Protein (g) -2.25 0.99 (P) -6.93 2.43
Fat (g) -1.50 0.96 (P) -5.34 2.34
Carbohydrate (g) -8.45 0.99 (P) -32.66 15.8
Fibre (g) -0.63 0.99 (P) -2.5 1.6
Calcium (mg) -6.20 0.99 (P) -48.1 35.7
Iron (mg) -0.60 0.97 (P) -1.92 0.72
Zinc (mg) -0.37 0.98 (P) -1.13 0.38
Folate (µg) -8.44 0.98 (P) -37.5 20.6
Vitamin C (mg) -0.59 0.99 (P) -11.4 10.2
Vegetables (g) -1.0 (Median) 0.96 (S) -0.65 1.43

Some results have been calculated using statistical techniques based on the published data.

For further information on statistical terms click on Statistical tests used in validation studies

All correlations coefficients in the table are unadjusted unless stated otherwise. For adjusted correlation coefficients and other statistical methods used in the study e.g. paired t-tests, please read the validation articles.

  • # Adjusted
  • † Energy adjusted.
  • ‡ For loge-transformed, energy-adjusted nutrient intakes.
  • ^ Adjacent included.
  • ᵟ Participants provided identical responses.
  • (w) = Weighted.

Lazarte CE, Encinas ME, Alegre C, Granfeldt Y. Validation of digital photographs, as a tool in 24-h recall, for the improvement of dietary assessment among rural populations in developing countries. Nutrition journal. 2012 Aug 29;11(1):61.