The Effects of a High Protein Breakfast on Appetite and Sleep in Young Adults

Young adults will consume the following breakfasts (in randomized order) for 7 days/pattern: 350kcal HP breakfasts (30g protein) in solid or beverage form or will skip breakfast. During the breakfast treatment periods, the participants will be provided with isocaloric breakfast meals containing 34% protein (30g protein), 40% CHO, and 26% fat. The participants will consume these meals each day throughout each of the 7 day testing periods. During the breakfast skipping treatment period, the participants will skip breakfast every morning with nothing to eat or drink (besides water) until 12:00 pm. During the acclimation days (i.e., days 1-6), participants will eat their breakfasts at home or work or simply skip the morning meal. An actigraph (to assess key indices of sleep) will be continuously worn and sleep diaries will be completed for all 7 testing days. During the afternoon of Day 3, the participant will arrive at the University of Missouri-Physical Activity and Wellness Center (MU-PAW) and fitted with a Continuous Glucose Monitor (CGM) measure glycemic control over the next 3 days. On day 6, the participant will complete hourly appetite questionnaires, consume a standardized dinner meal, and complete a salivary sample prior to sleep onset (sleep related hormones). On the 7th day of each pattern, the participants will report to the MU-PAW in the morning to complete the respective testing day. The participants will begin the testing day by either skipping breakfast or consuming their respective breakfast meal. Blood samples, salivary samples, and assessments of perceived appetite will be collected/completed at specific times throughout the day. Prior to lunch, a brain scan will be completed using functional magnetic resonance imaging (fMRI) to identify bain activation patterns in response to food pictures. Following the fMRI, the participants will be provided with an a standardized lunch. The participants will then complete the remainder of the testing day. An ad libitum food buffet will be provided for the participants to consume after their departure at home throughout the remainder of the day. . They will continue to wear the actigraph and eat/drink from the ad libitum packout cooler until going to bed that evening. Lastly, participants will complete a salivary sample and sleep diary immediately before bed. Between days 8-10, the participants will return all testing day equipment and the packout cooler, including all empty wrappers and any uneaten foods. A 3-7 day washout period will occur between patterns in which the participant will return to their habitual (i.e. pre-study) breakfast behaviors. Study outcomes include morning, mid-day, afternoon, and evening appetite, satiety, pleasure, perceived energy/sleepiness, hormonal responses (plasma glucose, insulin, ghrelin, PYY, melatonin, and cortisol concentrations), sleep indices (i.e total sleep time, sleep efficiency, perceived sleep quality), brain activation patterns, evening energy intake, and daily energy intake.