Ad libitum vending machine diet.
chocolate milk
For the last 3 days of each inpatient stay, participants were given ad libitum access to a computerized vending machine (StarFood, Necta). The macronutrient self-selection paradigm procedure (MSSP) was used to select items for stocking the vending machine (Vending machines were stocked with traditional breakfast, lunch, dinner, and snack items. Beverages and condiments were also included in the vending machine, and consumption of these items was also recorded. SSB included fruit juices, lemonade, chocolate milk, and regular sodas. Each participant had access to 1 vending machine that only they could access. Once foods were selected, participants were instructed to eat in the dining area, and no food was allowed in the participant’s room. All uneaten food and wrappers were returned to the Metabolic Kitchen to be weighed. The vending machines were restocked daily at 8 a.m. with items that had been removed in the previous 24 hours. All foods were weighed to the nearest tenth of a gram on a digital scale (Mettler Toledo MS Series) prior to placing them in the computerized vending machine, and the remainder of any uneaten foods were weighed after consumption. Energy and macronutrient composition of the foods consumed from the vending machine were calculated using a computerized nutrition database (ProNutra, Viocare Inc.).Vending machine foods were retrospectively categorized as either ultraprocessed or non-ultraprocessed based on NOVA categories (Statistical analyses of caloric intake from Vending Machines were performed using IBM SPSS Statistics (28.0.1.1). Repeated-measure mixed model analyses were used to assess differences in intake of energy, macronutrients, and percent of calories from MSSP and SSB among 17 participants completing both 3-day ad libitum periods.