This is a notoriously difficult thing to do well. Often we settle for something easier. Things like consumption checklists (as is ICFI indicator sets), food frequency questionnaires (FFQs), and other groups and scores methods are used. These have been validated against weighed intakes. A reference that I have found very useful is "Design Concepts in Nutritional Epidemiology" By Barrie Margetts and Mike Nelson. I have the 1991 edition which has good coverage and is quite cheap on Amazon. Other useful texts are "Principals of Nutritional Assessment" by Rosalind Gibson and "Nutritional Epidemiology" by Walter Willet.

My own (with cherished colleagues) small contribution to this field is decribed in:

Aaron GJ, Sodani PR, Sankar R, Fairhurst J, Siling K, Guevarra E, et al. (2016). Household Coverage of Fortified Staple Food Commodities in Rajasthan, India. PloS One, 11(10)

This uses an "adulte male equivalents" (AME) approach to the shared food problems for RDAs from fortified staples. There is some supporting material here:

Aaron GJ, Strutt N, Boateng NA, Guevarra, E, Siling K, Norri, A, et al. (2016). Assessing Program Coverage of Two Approaches to Distributing a Complementary Feeding Supplement to Infants and Young Children in Ghana. PloS One, 11(10)

This was part of the same series of reports on GAIN's FACT (food assessment and coverage tools) method development.

I hope this is of some use.

Hi -

This is indeed challenging. In addition to her excellent textbook (for which Dr. Myatt provided the link) Dr. Gibson developed a methodology for dealing with this situation, along with her colleague Dr. Elaine Gibson. Their approach involves "pre-training" the respondent mothers a few days in advance and in some cases providing plate, bowl, and/or cup. This method has been successfully used and adapted in many countries. Here is the link for their manual:

http://www.harvestplus.org/sites/default/files/tech08.pdf

Although every effort is made, this approach can change mother's feeding behavior. But it is important to note that weighed food records are also likely to change behavior. So we do the best we can. This may still be more accurate for capturing young child intake than the AEU method, which usually assumes that all foods are divided in the household in direct proportion to energy requirements.

For other extremely helpful resources and guidance on selection of methods, you can visit the Dietary Assessment Primer of the US National Cancer Institute, at:

https://dietassessmentprimer.cancer.gov/

Hope this is helpful.