The Effects of Protein Source on Appetite Control, Satiety, and Subsequent Food Intake
The Effects of Protein Source on Appetite Control, Satiety, and Subsequent Food Intake
The investigators propose a randomized, tightly-controlled breakfast trial in normal to
 overweight adults that will test whether the consumption of various types of protein-rich
 meals, containing ~24g of protein, will differentially alter food intake and meal initiation
 through proposed appetite and satiety mechanisms.

 Aim 1: To examine whether the consumption of protein-rich meals that vary in protein quality
 (source) effect:

 1. postprandial feelings of hunger, fullness, desire to eat, prospective food consumption

 2. postprandial fluctuations in key appetite and satiety hormones

 3. eating initiation (i.e., motivation to eat (again))

 4. food cravings

 Aim 2: To examine whether the consumption of protein-rich meals that vary in protein quality
 (source) effect:

 1. energy intake and food choice within the breakfast meal

 2. energy intake and food choice at the next eating occasion

 3. energy intake and food choice across the entire day
Experimental Design: For 3 consecutive days/pattern, the participants will consume the
 respective treatment, at home, between 7-9 am and refrain from eating or drinking anything
 other than water until 12:00pm. On day 3, the participants will consume a standardized dinner
 at home the night before testing. On day 4, the participants will report to the research
 facility between 6-8 am to complete each 5-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 questionnaires (and/or blood samples) will be completed. At time
 +0 min, the respective breakfast treatment will be provided. Immediately following the first
 swallow of the breakfast meal, the participants will be given a questionnaire assessing the
 palatability. The participants will consume the breakfast within 20 min. After breakfast, the
 participants will continue to complete the questionnaires (and/or blood samples) every 30 min
 throughout the 5-h postprandial period. Throughout the day, the participants will also
 indicate if/when they would like to eat again. Regardless of the participants' meal timing
 request, at +240min post-breakfast, the participants will be provided with an ad libitum
 lunch. For the lunch meal, the participants will be given 30 min to "consume as much or as
 little as possible until comfortably full." Following these procedures, the participants will
 be allowed to leave the facility. The next day, a dietary recall will be performed to assess
 daily energy intake across the previous day. Lastly, on day 5 (at home), the participants
 will be provided with their respective breakfast along with additional carbohydrate and/or
 fat foods. Once the treatment breakfast is consumed, the participants can select and consume
 as much of the additional foods as they wish to consume within the breakfast time period (30
 minutes).
Inclusion Criteria:

 -  Males and females

 -  All ethnicities

 -  Age: 20-40y

 -  BMI/BMI Percentile: 18.5-29.9 kg/m2

 -  Consumes breakfast (>110 kcal prior to 10 am) at least 5 days/week for the past year

 -  Never smoked or used other tobacco products

 -  Willing to consume the study breakfasts

 -  Generally healthy (as assessed by Medical History Questionnaire)

 -  Health conscious as determined by answering yes to 3 pre-screening health & lifestyle
 questions

 -  Rating of ≥ 5 illustrating a minimum of "neither like nor dislike on a hedonic 9 pt
 taste test of all testing treatments

 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 ≥4.5kg over the past 6 months

 -  Donated (or plan to donate) blood through the American Red Cross within the past 6
 months (or future 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

 -  Clinically diagnosed with a sleeping disorder