The Effects of Protein Source on Appetite Control, Satiety, and Subsequent Food Intake: A Clinical Screening Study
The Effects of Protein Source on Appetite Control, Satiety, and Subsequent Food Intake: A Clinical Screening Study
Primary Objective: To examine whether the consumption of preloads varying in protein quality
 effect subsequent meal energy and macronutrient content

 Secondary Objectives: To examine whether the consumption of preloads varying in protein
 quality effect postprandial feelings of hunger, fullness, desire to eat, prospective food
 consumption, and eating initiation.

 Exploratory Objective: To examine whether the consumption of preloads varying in protein
 quality effect postprandial cognitive performance.
The investigators propose the following acute, randomized crossover study to compare 5,
 isocaloric yogurt-based preloads containing 20, 30, or 40 g pea protein; 20 g whey protein;
 and an isocaloric carbohydrate (control).

 For 3 consecutive days/pattern, the participants will consume the respective treatment, at
 home, between 7-9 am, based on their habitual breakfast time. (These days are implemented to
 allow for the acclimation to the respective preload. Using this approach, the participant
 becomes familiar with the taste profile along with the practice of consuming a breakfast
 'shake' so that the testing day more closely assimilates the habitual effects of the preload
 on appetite, satiety, and food intake.)

 On day 4, the participants will report to the research facility 1 h prior to their habitual
 breakfast time to complete each 4-h testing day. Upon arrival to the facility, each
 participant will become familiarized with the testing day procedures. At time -15 min, a
 baseline set of computerized appetite/satiety and cognitive function questionnaires will be
 completed. At time 0 min, the respective preload will be provided. Immediately following the
 first swallow of the preload, the participants will be given a questionnaire assessing the
 palatability. The participants will consume the preload within 10 min. Afterwards, the
 participants will continue to complete the questionnaires every 30 min throughout the 4-h
 postprandial period. In addition to these questionnaires, participants will complete a
 cognitive function paradigm at -30 min, +90 min, and +180 minutes in order to assess memory,
 executive function, attention, and reaction time. Throughout the day, the participants will
 also indicate if/when they would like to eat again. Regardless of their meal timing request,
 at 4-h post-breakfast, lunch will be provided. The participants will be given 30 min to
 "consume as much or as little as they wish until comfortably full." Following these
 procedures, the participants will be allowed to leave the facility. There will be a 3-7 day
 washout period between testing days.
Inclusion Criteria:

 -  Normal weight (BMI: 18.0-24.5 kg/m2)

 -  No history of smoking

 -  No metabolic or hormonal conditions/diseases that influence metabolism, appetite, or
 food intake

 -  No past history of surgical interventions for the treatment of obesity

 -  No weight loss/gain (≥10 lb. in the past 6 months)

 -  No medication that would influence directly appetite or cognition

 -  No change in any medications (over the past 3 months)

 -  Not currently/previously on a special diet such as Atkins/Ketogenic, high protein,
 vegan, vegetarian, etc.

 -  Habitually consumes breakfast (i.e., of at least 350 kcal on ≥ 5 days/wk prior to 9 am

 -  Habitually consumes lunch (i.e., of at least 350 kcal on ≥ 5 days/wk approximately 4 h
 after breakfast

 -  Not clinically diagnosed with an eating disorder such as anorexia, bulimia,
 night-eating syndrome

 -  Displays a score of <4 on the Three Factor Eating Habits Questionnaire (TFEQ)

 -  No allergies and/or aversions to the food/ingredients included within the study

 -  No history of drug or alcohol abuse (i.e., >14 drinks/week)

 -  Willing to maintain current activity dietary patterns throughout the study

 -  Willing to consume all study breakfast and lunch foods

 -  Generally healthy, as assessed from the medical history questionnaire

 -  Rating of ≥ 5 illustrating a minimum of "neither like nor dislike on a hedonic 9 pt
 taste test of the breakfast preloads

 Exclusion Criteria:

 -  Clinically diagnosed with an eating disorder

 -  Metabolic, hormonal, and/or neural conditions/diseases that influence metabolism or
 appetite

 -  Currently or previously on a weight loss or other special diet (in the past 6 months)

 -  Gained/lost >10 lb. over the past 6 months

 -  Taking medication that would directly influence appetite (weight-loss drugs or
 antidepressant, steroid, or thyroid medication, unless dosage has been stable for at
 least 6 months)

 -  Not willing or able to complete all study testing procedures