Cheese

To develop the initial set of food items, the investigators examined existing instruments [8 (link),14 (link)] and reviewed the literature that identified major contributors to overall energy intake (e.g., [15 (link)]). This process allowed us to evaluate the foods listed in inventories that were developed for a specific limited purpose (e.g., a diabetic population, nonperishable foods, etc) as well as expand the items in our inventory to include foods known to be associated with energy intake in the population. In addition, based on literature that demonstrates a high correlation between readily accessible foods (i.e., foods in plain view) and their intake [3 (link)], two items were added to assess the accessibility of healthful foods within the main kitchen area and the refrigerator. Thus, we evaluated the literature and instruments to date, and added foods that provided a more comprehensive inventory of foods associated with dietary intake of adults in the US.
During the course of initial validity testing (Sample 1), changes in the number of items and instructions occurred. For example, participants were allowed to "write in" foods within given categories (e.g., dairy, fruits, vegetables), and if "write in" responses were found to be frequent, they were added as items on the inventory. During the validity testing with Sample 1, the HFI had 186 items while the final inventory administered to Sample 2 included 190 items.
HFI items are listed in a checklist type format with yes/no (1/0) response options. Higher scores represent greater availability. In addition, participants were instructed to check whether the vegetable, fruit, and bread items were fresh, frozen, dried or canned, as appropriate. The category order was set up to facilitate ease of completion, beginning with the refrigerated items, followed by frozen items, and non-perishable items. Participants are instructed to look for these foods in all areas of the home where food is stored, including the refrigerator, freezer, pantry, cupboard, and other areas (e.g., basement). Participants were informed that lower fat products may be labeled as "reduced-fat," "low-fat," "light," "nonfat," or "skim." Foods in the dairy, added fats, frozen desserts, prepared desserts, and savory snacks were categorized into regular-fat or reduced-fat groupings; beverages were categorized into regular sugar and low sugar categories; and foods in the two ready-access categories were further subgrouped into healthful and less healthful categories. Although the categorization of foods into healthful and less healthful categories may not be entirely straightforward, we assessed each food by its typical fat and sugar content when determining its category. To assess the overall obesogenic home food availability, a summative score was created that includes regular-fat versions of cheese, milk, yogurt, other dairy, frozen desserts, prepared desserts, savory snacks, added fats; regular-sugar beverages; processed meat; high-fat quick, microwavable foods; candy; access to unhealthy foods in refrigerator and kitchen. The obesogenic home food availability score potential range was from 0–71 (present sample: range = 9–53, M = 29.4, SD = 7.6). The HFI can be requested from the primary author. A table reflecting which foods are included in each food group/subgroup is provided in Additional file 1. The inventory took approximately 30–45 minutes to complete depending upon the amount of food stored in the home.

The touchscreen questionnaire used in the main study contained twenty-nine questions about diet and eighteen questions about alcohol. The touchscreen questionnaire asked about the frequency of consumption over the past year of the following food groups: cooked vegetables, salad/raw vegetables, fresh fruit, dried fruit, oily fish, other fish, processed meats, poultry, beef, lamb, pork, cheese, salt added to food, tea, water, as well as questions on the type of milk most commonly consumed, type of spread most commonly consumed, number of slices and type of bread most commonly consumed, number of bowls and type of breakfast cereal most commonly consumed, cups of coffee and type most commonly consumed, as well as questions on the avoidance of specific foods and food groups (eggs, dairy products, wheat, sugar), age last ate meat (for participants who reported never consuming processed meats, poultry, beef, lamb or pork), temperature preference of hot drinks, changes in diet in the past 5 years, and variation in diet. Four of the dietary questions used in the pilot study were altered slightly for the main phase: these were the questions on avoiding specific foods and food groups; spread type; bread type; and variation in diet. A total of 3776 participants completed only the pilot version of the touchscreen; for analyses on these questions the participants answering only the pilot version were excluded. Details of the possible answers for each dietary touchscreen question are given in the Supplementary Methods^{(6 ,7 )}. We also generated a partial fibre score from the touchscreen questionnaire using the questions on fresh fruit, dried fruit, raw vegetables, cooked vegetables, bread type and bread intake, and breakfast cereal type and breakfast cereal intake. Further detail on how we generated the partial score is given in the Supplementary Methods and Supplementary Table S1.

Consumption of ASF is the outcome variable for this study. The questionnaire asked mothers/caretakers what types of foods the child had eaten in the 24 h before the survey. Consumption of any of milk, yogurt, cheese, eggs, fish, meat (including beef, poultry, pork, lamb, and any other meat not mentioned), and organ meats (e.g., liver) was considered as ASF consumption. The variable was dichotomized into “No ASF consumption” (coded “0”) and “ASF consumption” (coded “1”).