Assessing the Validity of Measuring Energy Intake by Remote Food Photography Method as Compared to Doubly Labeled Water in Pregnant Women
Authors: Most Jasper , Vallo Porsha M , Altazan Abby D , Gilmore Anne L , Sutton Elizabeth F , Cain Loren E , Burton Jeffrey H , Martin Corby K , Redman Leanne M 
Published: November 2023

To improve weight management of pregnant women, there is a need to deliver specific, data‐based recommendations on energy intake or physical activity. This study investigated how to use an electronic reporting method of energy intake in pregnant women and evaluated its validity compared to total daily energy expenditure (TDEE).

23 obese (BMI: 36.9±1.3 kg/m2) pregnant women (28.3±1.1 years) used a Smartphone application to capture images of their food selection and plate waste in free‐living conditions for at least 6 days in early (13–16 weeks) and late (35–37 weeks) pregnancy. Energy intake by Remote Food Photography Method (RFPM) was evaluated compared to TDEE obtained by doubly labeled water over the same 7‐day period.

During 45 observation periods (n=23 × 2 visits, one abnormal TDEE excluded), pictures were captured on 290 (99%) days (6.4±0.1 days captured per observation, 9.0±0.4 pictures*d−1). Average energy intake reported by the RFPM was 1755±59 kcal*d−1 (range: 804 to 2729 kcal*d−1) which equals a 37%±2% (−68 to −11%) underestimate compared to TDEE (2807±51 kcal*d−1), consistent with earlier data from non‐pregnant adults where non‐personalized ecological momentary assessment (EMA) prompts were utilized. Meals (breakfast, lunch, dinner) were reported on 82% (reported meals vs total days) of possible occasions and accounted for 83±2% of total energy intake, while energy intake from snacks was 17±2%.

To investigate which factors contribute to compliance, we differentiated reported energy intake by days of the week (week vs weekend), type of phone (own vs study‐provided) and meal type (meals vs snacks). While we found no significant difference in the reported energy intake between week and weekend days, participants that captured pictures on their own phone compared to the study‐provided phone had significantly more pictures (P=.04) and consequently a higher energy intake (P=.13). Reported energy intake as snacks (%energy snack/total) was significantly associated with % reporting (% RFPM/DLW, R2=0.19, P=.03), indicating that reporting of snacks increased accuracy.

To understand how to improve data quality, we excluded days of likely underreporting by three criteria: <1000 kcal*d−1, <2 main meals*d−1 or <60% of TDEE. The accuracy of energy intake in comparison to TDEE increased significantly (+7±2%, +5±3% and +24±4%), yet 9, 9 and 45% of the days were excluded by these criteria, respectively. Despite these improvements none of the criteria increased the RFPM to an accuracy within 10% bounds (Two One‐Sided Test for Equivalence, −33±2%, −34±2% and −22±1%, all: P=1.00).

In summary, using an electronic reporting method (RFPM), energy intake in obese pregnant women does not accurately estimate energy intake as compared to DLW. However, data quality improves when participants use their own phones and by applying criteria to eliminate unrealistic data. Further evaluation of EMA prompting in this population is needed to improve compliance, specifically for snacks and frequent small meals.

Support or Funding Information

NIH R01DK099175, LaCats U54GM104940 and NORC P30DK094418