What you need is a sack. A gunny sack, also known as hessian or tow sack, made from burlap, jute, hemp, or sisal. Very crude, very thick, definitely no way to see what’s in it. Preferably black and with a huge Uphold logo and a red ink stamp “I need my privacy!” A sack!
Reproducibility and validity of a food-frequency questionnaire for use among low-income Brazilian workers. Public Health Nutr. 2003;6:821–7. Article PubMed Google Scholar Nouri M, Ghazizahedi S, Mohajeri SA. Relative validity and reproducibility of a semi-quantitative food frequency questionnaire...
Among those potential confounders, we chose a child’s socioeconomic status (SES) (household income), physical activity, stress level, and mother’s BMI at baseline (age nine or 10 years) as covariates. Parental socioeconomic information (household income) and maternal height and weight were ...