FITS and KNHS Overview: Methodological Challenges in Dietary Intake Data Collection among Infants, Toddlers, and Children in Selected Countries

Alison L. Eldridge

FITS (the Feeding Infants and Toddlers Study) began in 2002 as a large-scale national telephone survey to study the eating patterns and nutrient intakes of infants and young children in the USA and was followed in 2008 by a second FITS. Both studies helped to fill a gap in knowledge and confirmed Nestlé’s commitment to understanding dietary patterns among children in these vulnerable age groups. 

Building on the FITS model, Nestlé expanded their research program to include older children and launched the KNHS (Kids Nutrition and Health Study) in 2014. Together, FITS and KNHS investigate nutrient intakes, food groups consumed, food sources of nutrients, meal patterns, feeding practices, household demographic factors, and key behaviors related to energy intake and expenditure in infants and children in different countries around the world [1–5]. 

In each FITS and KNHS country, dietary intake was assessed using trained interviewers and multiple-pass 24-h recalls on 1 or more days (Table 1). The FITS and KNHS used data from national nutrition and health surveys when available. This was the case for KNHS in Australia, China, and the USA, and for FITS and KNHS in Mexico, the Philippines, and Russia. In China and the USA, the national surveys did not include infants or toddlers, so we collected data using similar methods (MING in China and FITS in the USA). 

Although many countries with comprehensive national nutrition surveys use dietary recalls for individual-level intake estimations, other aspects of the survey methodology differed considerably. National surveys used in FITS and KNHS have collected data on intake at 1 day (Mexico), 2 nonconsecutive days (Australia, the Philippines, and the USA), or 3 consecutive days of intake (China). In Russia, 2 days of intake data were collected, 1 in spring and 1 in autumn. Food composition tables varied by country, both in number of nutrients and completeness of the databases. Different countries used different age classifications and different food grouping schemes. Not all surveys recorded details about the meals or times when foods were consumed. 

Table 1. FITS and KNHS study countries, sources of data, participant characteristics, and dietary assessment methods used
Study Name Age Participants,n Dietary assessment method
Australia 2011-2012 National Nutrition and Physical Activity Survey (NNPAS) 2 years and older 2,213 (4-12 years) Two 24-h recalls
China FITS 2011-2012 Maternal Infant Nutrition Growth (MING) Birth to 35 months 1,409 (0-35 months) One 24-h recall
China KNHS 2011 China Health and Nutrition Survey (CHNS) 2 years and older 1,460 (4-13 years) Three consecutive-day 24-h recalls
Mexico 2012 Mexican National Health and Nutrition Survey (ENSANUT) All ages 2,057 (0-47 months) 3,985 (4-13 years) One 24-h recall
The Philippines 8th National Nutrition Survey 2013-2014 All ages 1,837 (0-35 months) 8,992 (3-12 years) -
Russia 2013 Russian National Nutrition Survey All ages 4,612 (0-47 months) 22,771 (4-13 years) Two 24-h recalls, spring and fall
US FITS 2016 Feeding Infants and Toddlers Study Birth to 47 months 3,235 (0-47 months) Two 24-h recalls
US KNHS 2009-2012 National Health and Nutrition Examination Survey 2 years and older 3,647 (4-13 years) Two 24-h recalls

To address these issues, a common analysis approach has been applied across all FITS and KNHS countries. The standard analysis evaluates nutrient intakes by looking at means and distributions of intakes, and compares them with established dietary reference intakes. We evaluate meal patterns, including the percent consuming and skipping different meals and snacks and timing of consumption. Food groups are applied to all foods and beverages reported, and these are used to look at eating patterns, including the complementary feeding transition, and to understand the top sources of energy and nutrients in the diet. 

As much as possible, the FITS and KNHS have standardized reporting of age categories (typically 0–5.9, 6–11.9, 12–23.9, and 24–47.9 months, and 4–8 and 9–13 years of age) and food grouping systems so comparisons could be made. Aligning food groups is challenging as the specificity needed for some food groups differs depending on the country. We have supported work to impute nutrient values to complete datasets for nutrients of interest when needed (e.g., total sugar in Mexico and China; fiber, sodium, and total sugar in the Philippines). 

In summary, the FITS and KNHS are part of a global Nestlé research initiative to study dietary intakes and related behaviors in infants, toddlers, and children. We have evaluated national survey data where they exist, and when not available, we have conducted our own studies to fill the gaps in knowledge. To address methodological issues, we implemented a common analysis approach, supported work to impute nutrient values to complete food composition databases, and harmonized food grouping systems so comparisons could be made across countries. This overview is accompanied by case studies sharing results from countries that comprise the current FITS and KNHS.


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