WWEIA/NHANES 2021-2023

What We Eat in America, NHANES August 2021 - August 2023

Notice to Dietary Data Users (developed by CDC/National Center for Health Statistics) provides additional information on the changes that pertain to the dietary data collection.

Intake Days

Two days of dietary intake data are available. 

• Day 1 is collected by telephone. The Day 1 files include:
  • 6,694 individuals with a complete intake (21 participants who had an unreliable day 1 intake, but a reliable day 2 intake were included in the data set as Day 1 intakes)
  • 60 breastfed individuals
• Day 2 is collected by telephone 3 to 10 days later. The Day 2 files include:
  • 5,830 individuals with a complete intake
  • 49 breastfed individuals

 

Data File Descriptions

Four dietary intake files are available.

• Individual Foods Files:  DR1IFF_L (Day 1) and DR2IFF_L (Day 2)
  The Individual Foods Files include, for each interview day, one record for each food consumed by a participant.  Each record identifies the intake day of week, the time and name of the eating occasion for the food, and the following food-specific data:
  
  
  • Food, identified by a USDA food code
  • Whether food was eaten in combination with other foods (for example, milk added to cereal)
  • Amount of food consumed
  • Amounts of food energy and 64 nutrients/food components provided by the food amount
     
• Total Nutrient Intakes Files:  DR1TOT_L (Day 1) and DR2IFF_L (Day 2)
  The Total Nutrient Intakes Files contain, for each interview day, one record for each participant. Each record includes daily total intakes of food energy and 64 nutrients/food components, daily intake of water, and whether the amount of food consumed was usual, much more than usual, or much less than usual. The Day 1 file also includes information on salt use, whether the participant is on a special diet (weight loss, low carbohydrate, etc.), and frequency of fish and shellfish consumption for population subsets. 

 

Sample Weights

• Sample weights specific to the dietary intake data adjust for (a) the additional non-response and (b) the differential allocation by day of the week for the dietary intake data collection.
• Two sets of weights—Day 1 weights (WTDRD1) are to be applied to Day 1 data; two-day weights (WTDR2D) are to be applied when both days are used (Day 1 and Day 2).
• Read about the dietary intake sample weights in the analytical notes section of the documentation.