To assess the validity of food photographs in portion size estimation among adolescent girls in Mozambique. The study was carried out in preparation for the larger ZANE study, which used the 24 h dietary recall method.

Life-sized photographs of three portion sizes of two staple foods and three sauces were produced. Participants ate weighed portions of one staple food and one sauce. After the meal, they were asked to estimate the amount of food with the aid of the food photographs.

Zambezia Province, Mozambique.

Ninety-nine girls aged 13–18 years.

The mean differences between estimated and actual portion sizes relative to the actual portion size ranged from −19 % to 8 % for different foods. The respective mean difference for all foods combined was −5 % (95 % CI −12, 2 %). Especially larger portions of the staple foods were often underestimated. For the staple foods, between 62 % and 64 % of the participants were classified into the same thirds of the distribution of estimated and actual food consumption and for sauces, the percentages ranged from 38 % to 63 %. Bland–Altman plots showed wide limits of agreement.

Using life-sized food photographs among adolescent Mozambican girls resulted in a rather large variation in the accuracy of individuals’ estimates. The ability to rank individuals according to their consumption was, however, satisfactory for most foods. There seems to be a need to further develop and test food photographs used in different populations in Sub-Saharan Africa to improve the accuracy of portion size estimates.

To assess the errors between estimates of amounts based on photographs and actual quantities of food presented to adults or eaten on the previous day.

A photographic atlas was constructed by taking digital photographs of three pre-weighed portion sizes of 212 traditional Lebanese dishes. In a first approach, ten portions of real pre-weighed foods were assessed using the photographic atlas. In a second approach, the participants weighed all foods consumed at one meal and recalled the amount of food that was eaten the previous day using the photographic atlas. Differences between actual quantities and estimation were assessed using a signed rank test (P < 0·05). Spearman's correlation coefficients and bias (Bland–Altman plot) between the methods were calculated.

Lebanese university canteen and Lebanese homes.

Forty adults (twenty males, twenty females) completed the first protocol and fifty adults (twenty-five males, twenty-five females) completed the second protocol; all were volunteers aged 21 to 62 years.

Mean differences between actual and estimated portion sizes by photographs were between −13·1 % and +24·5 % when pre-weighed foods were presented, and between −10·4 % and +3·8 % when foods were consumed the day before. No significant differences were found between actual and estimated portion sizes except for three dishes (loubieh bil zeit, tabbouleh and yachnet bazella). Bland–Altman plots showed good agreement for all dishes with a negligible bias of −0·2 g between estimated and presented portions, and −6·3 g between estimated and eaten portions.

In the Lebanese diet, food photographs seem a reliable tool for quantification of food portion sizes.

To validate food photographs for food portion size estimation of frequently consumed dishes, to be used in a 24-hour recall food consumption study of pregnant women in a rural environment in Burkina Faso. This food intake study is part of an intervention evaluating the efficacy of prenatal micronutrient supplementation on birth outcomes.

Women of childbearing age (15–45 years).

A food photograph album containing four photographs of food portions per food item was compiled for eight selected food items. Subjects were presented two food items each in the morning and two in the afternoon. These foods were weighed to the exact weight of a food depicted in one of the photographs and were in the same receptacles. The next day another fieldworker presented the food photographs to the subjects to test their ability to choose the correct photograph.

The correct photograph out of the four proposed was chosen in 55% of 1028 estimations. For each food, proportions of underestimating and overestimating participants were balanced, except for rice and couscous. On a group level, mean differences between served and estimated portion sizes were between −8.4% and 6.3%. Subjects who attended school were almost twice as likely to choose the correct photograph. The portion size served (small vs. largest sizes) had a significant influence on the portion estimation ability.

The results from this study indicate that in a West African rural setting, food photographs can be a valuable tool for the quantification of food portion size on group level.

To evaluate the errors incurred by young adults using single portion size colour food photographs to quantify foods and nutrients consumed at six meals on two non-consecutive days.

Breakfast menus remained the same for the 2 days; but lunch and dinner menus varied. The amounts of food eaten by individuals were determined by weighing individual serving dishes pre- and post-consumption. The day after eating, all foods consumed were quantified in terms of fractions or multiples of the amounts shown in the food photographs.

Thirty adult volunteers (15 male, 15 female), aged 18–36 years, completed the protocol for day one; 27 (90%) completed day two.

Some foods were more difficult to quantify accurately than others. The largest error range was −38.9% to +284.6% (cheese), whereas the smallest errors were incurred for juice (−21.5% to +34.6%, day one). All subjects who consumed muesli (day one) overestimated (+3.7% to +113.7%). No other foods were consistently over-or underestimated. For foods consumed at breakfast by the same subjects on both days, individual estimation errors were inconsistent in magnitude and/or direction. At the group level, most nutrients were estimated to within ±10% of intake; exceptions were thiamin (+10.5%, day one) and vitamin E (−10.1%, day one; −15.3%, day two). Between 63% and 80% of subjects were correctly classified into tertiles on the basis of estimated intakes.

Despite some large food quantification errors, single portion size food photographs were effective when used to estimate nutrient intakes at the group level. It remains to be established whether, under the conditions used in this study, more photographs per food would improve estimates of nutrient intake at the individual level.

In order to obtain a measure of nutrient intake, a measure or estimate of the amount of food consumed is required. Weighing foods imposes a large burden on subjects, often resulting in underreporting. Tools are available to assist subjects in providing an estimate of portion size and these include food photographs. The application of these tools in improving portion size estimation by children has not been investigated systematically.

To assess the accuracy with which children are able to estimate food portion sizes using food photographs designed for use with adults, and to determine whether the accuracy of estimates is improved when age-appropriate portion size photographs are provided.

Original data from three separate studies, on the accuracy of portion size estimates by adults using food photographs, by children using adult photographs and by children using age-appropriate photographs, are analysed and compared.

One hundred and thirty-five adults aged 18 to 90 years and 210 children aged 4 to 11 years.

Children's estimates of portion sizes using age-appropriate food photographs were significantly more accurate (an underestimate of 1% on average) than estimates using photographs designed for use with adults (an overestimate of 45% on average). Accuracy of children's estimates of portion size using age-appropriate photographs was not significantly different from that of adults. Children overestimated a food's weight by 18% on average and adults underestimated by 5%.

Providing children with food photographs depicting age-appropriate portion sizes greatly increases the accuracy of portion size estimates compared with estimates using photographs designed for use with adults.