To examine the comparability of fruit and vegetable (F&V) intake data in the USA from 2001 to 2014 between data acquired from two national data collection programmes.

Cross-sectional analysis. Linear regression models estimated trends in daily per capita intake of total F&V. Pooled differences in intake of individual F&V (n 109) were examined by processing form (fresh, frozen, canned, dried and juice).

What We Eat in America (WWEIA, 2001–2014) and Loss-Adjusted Food Availability data series (LAFA, 2001–2014).

No temporal trends were observed in daily per capita intake of total F&V from 2001 to 2014 using WWEIA and LAFA. Modest differences between WWEIA and LAFA were observed in mean pooled intake of most individual F&V.

WWEIA and LAFA produced similar estimates of F&V intake. However, WWEIA may be best suited for monitoring intake at the national level because it allows for the identification of individual F&V in foods with multiple ingredients, and it is structured for sub-population analysis and covariate control. LAFA does retain advantages for other research protocols, specifically by providing the only nationally representative estimates of food losses at various points in the food system, which makes it useful for examining the adequacy of the food supply at the agricultural, retail and consumer levels.

Estimates of fruit and vegetable (FV) consumption vary depending on intake definition, which may be determined by research purpose. Researchers have used two methods to evaluate intake: epidemiological and behavioural. The present study describes FV intake by adults using epidemiological v. behavioural approaches.

One-day dietary intake data from What We Eat In America, National Health and Nutrition Examination Survey 2009–2012 were used. Sample weights were used to produce nationally representative estimates. FV intake (in cup-equivalents (CE)) was estimated using the Food Patterns Equivalents Database. The epidemiological method considered all FV after disaggregating foods and beverages. The behavioural method included foods that provided at least 0·2 CE FV per 100 g, and excluded sources high in fat, added sugar and Na.

Nationally representative survey of the US population.

Adults (n 10 563) aged ≥20 years.

For epidemiological v. behavioural, fruit intake was 1·1 v. 1·0 CE for males and 1·0 v. 0·9 CE for females. Vegetable intake was 1·8 v. 1·1 CE for males and 1·5 v. 1·0 CE for females.

The definition of FV intake affects estimates of consumption by the population and is an important consideration when planning and comparing research studies. The method used should align with research goals to assure accurate interpretation and validity of results.

To provide updated estimates of drinking water intake (total, tap, plain bottled) for groups aged ≥1 year in the USA and to determine whether intakes collected in 2005–2006 using the Automated Multiple-Pass Method for the 24 h recall differ from intakes collected in 2003–2004 via post-recall food-frequency type questions.

Cross-sectional, observational study.

What We Eat in America (WWEIA), the dietary intake component of the US National Health and Nutrition Examination Survey (NHANES).

Individuals aged ≥1 year in 2003–2004 (n 8249) and 2005–2006 (n 8437) with one complete 24 h recall.

The estimate for the percentage of individuals who reported total drinking water in 2005–2006 was significantly (P < 0·0000) smaller (76·9 %) than that for 2003–2004 (87·1 %), attributable to a lower percentage reporting tap water (54·1 % in 2005–2006 v. 67·0 % in 2003–2004; P = 0·0001). Estimates of mean tap water intake differed between the survey cycles for men aged ≥71 years.

Survey variables must be examined before combining or comparing data from multiple WWEIA/NHANES release cycles. For at least some age/gender groups, drinking water intake data from NHANES cycles prior to 2005–2006 should not be considered comparable to more recent data.