A Comparison of Satiety Effects Two Commercially Available Snack Bars

Overview

The researchers are investigating the satiety effects of two commercially available snack bars. Qualified participants are age 18-65 with a body mass index of 18.5 to 29.9 kilograms of body weight per meter squared in height who are in good metabolic health. Participants will engage in two study visits conducted at the Indiana University--Bloomington Innovation Center. Study visits are separated by a 1-14 day washout period. Prior to each study visit, participants are asked to engage in normal activity and to refrain from strenuous exercise. Furthermore, subjects are asked to consume a typical diet the day prior to the study visit with one caveat; they are to consume standard frozen dinners (evening meal) of their choosing between 7-8 PM and to remain fasted afterward except for water and non-caloric beverages until the study visit the following day. The amount of food provided for the evening meal is estimated using a standard calorie calculator based on the Mifflin-St. Jeor equation and an estimate of their activity level. Subjects are instructed to consume only as much of the provided food as needed to become comfortably full as they would ordinarily. Subjects record their diet for the day. Upon arrival at the Innovation Center between 8-8:40 AM, compliance with the prior day protocol is verified through interview, and the diet record is reviewed. Participants consume 300 kcal of snack bars and complete visual analogue scales to assess hunger, fullness, desire to eat, and satisfaction at fasting and at 30 minute intervals from the fasting measurement for 2 hours. Immediately after consuming the snack bars, subjects complete a sensory evaluation of the snack bars. Fifteen to thirty minutes after completion of the final visual analogue scale, subjects will be presented with an individual buffet which they consume ad libitum until comfortably full. A second study visit that mirrors the first but with different bars is conducted after the washout period (1-14 days).

The study protocol is initiated after enrollment with a Food Frequency Questionnaire and a Three-factor eating questionnaire conducted during the screening visit after the participant's qualifications have been verified. After the questionnaires have been completed, the study visits and food pick ups are scheduled according to the availability of the subject and the study calendar. At the end of the screening appointment, the subject selects the frozen dinners to be consumed the evening prior to the study visit. The study is a crossover design in which investigators will assess the immediate effects of a single meal of two commercially available snack bars on subjective feelings of satiety over 2 hours and on energy and nutrient intake from a subsequent meal 2:15 to 2:30 following consumption of the bars. Study visits will be scheduled between 1 and 14 days apart. Subjects will consume a standard meal between 7 and 8 PM the evening prior to each study visit and complete a satiety questionnaire after finishing the meal. The subjects record all food consumed the day prior to the study visit including the dinner meals provided by the study. Participants will pick up food at the Indiana University-Bloomington School of Public Health the day prior to the scheduled study visits. This visit consists of dispensing the evening meals in lunch coolers packed with icepacks and the frozen meals the participant selected in the screening appointment. The study visit protocol for the following day is reviewed briefly. Appointment reminders are set up as emails and calendar invitations instructing the participant to consume the meals between 7-8 PM that night, to complete a satiety questionnaire, the link to which is embedded in the emails, and to remain fasted except for water and non-caloric beverages until the study visit the next day. Participants are offered a paper version of the satiety questionnaire if they so desire. The satiety questionnaire asks the participants to evaluate their feelings of hunger, fullness, desire to eat, and satisfaction with the previous meal. Desire to eat is differentiated to the participant as a desire to consume food regardless of their state of hunger while satisfaction is differentiated from fullness to the participants as a psychological sensation of contentedness and not a physical sensation of fullness. The same questionnaire is used for all time points during each study visit. Participants are asked to refrain from consuming caffeine in the morning. A specific arrival time is set for arrival at the Innovation Center the following day between 8 and 8:40 AM. After the subject arrives at the IU-Bloomington Innovation Center, coolers and icepacks are collected, compliance with the study protocol is confirmed. Next the diet record is reviewed by study personnel. Participants may be asked to clarify entries made on the diet record. Participants are invited to a room where as many as 3 participants at a time will undergo the study protocol. Subjects are allowed to interact with each other but are instructed to refrain from discussing the snack bars. A baseline satiety questionnaire is completed before the snack bars are offered with a bottle of water. Participants are instructed to enter "1" with regard to satisfaction with the meal at this fasted time point. Ad libitum water intake is allowed throughout the study visit. The participants are instructed to consume two snack bars comprising 300 kcal as quickly and comfortably as possible. After the subjects consume the bars, study personnel provide the participant with a sensory evaluation, either printed or electronic, which asks the subject to evaluate the bars in terms of overall taste, sweetness, saltiness, savory, desire to eat more, with the meal, and fullness/satiation. Participants complete the sensory evaluation after having consumed both bars. If participants are unable to consume both bars, the sensory evaluation is not completed, and the experimental protocol is terminated for that subject. The subjects remain in the room are are allowed bathroom breaks, to entertain themselves with their own audio devices, to read, and to work. Participants are prohibited from bringing and consuming outside food and from exercising during the study protocol. Satiety questionnaires are completed every 30 minutes from fasting. An electronic timer is provided with a flow sheet denoting the times for the satiety questionnaires to be completed. Participants write the times that they completed each iteration of the satiety questionnaire. Participants are monitored periodically for compliance and electronic recording of the questionnaires is monitored. After 2 hours the penultimate satiety questionnaire for the study visit is completed. Subjects are informed that they will be escorted to a lunch buffet consisting of grilled hamburger patties, grilled chicken, brioche buns, sliced tomatoes, sliced medium cheddar cheese, mayonnaise, mustard and ketchup, a fruit tray with individual portions of watermelon, cantaloupe, strawberries and blueberries, a bowl of potato chips, a bowl of mixed, salted nuts, chocolate chip cookies, and whipped cream to add to any of the food they choose. Participants are instructed to "serve themselves as much of the food as they care to consume and to consume it until comfortably full as quickly and comfortably as possible." Participants log the time that they finished the meals and complete a final satiety questionnaire after lunch. Each food item is weighed by study personnel before and after the participants dine. A second study visit is conducted that mirrors the first with a different type of snack bar. Start times for the protocol and the buffet lunch are matched as closely to the first study visit as possible.