The Effects of Protein Source on Appetite Control, Satiety, and Subsequent Food Intake
Condition: Appetitive Behavior
Study type: Interventional

Summary: 
      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
    

Detailed description: 
      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).
    

Intervention name(s): Micellar Casein (#1); Micellar Casein (#2); Calcium Caseinate; Sodium Caseinate; Milk Protein Isolate; Pure Protein Blend; Whey Protein Isolate; Native Whey Protein Isolate; Soy Protein; Pea Protein; Native Whey: Micellar Casein (50:50) blend; Carbohydrate Control
Intervention type(s): Other; Other; Other; Other; Other; Other; Other; Other; Other; Other; Other; Other
Intervention description(s): The study participants will be provided with breakfast meals to consume. The energy content of the breakfast meals will be standardized to ~250 kcal. The meals will include the same fat content but will contain protein sourced predominantly from micellar casein. All ingredients are GRAS listed and approved.; The study participants will be provided with breakfast meals to consume. The energy content of the breakfast meals will be standardized to ~250 kcal. The meals will include the same fat content but will contain protein sourced predominantly from micellar casein. All ingredients are GRAS listed and approved.; The study participants will be provided with breakfast meals to consume. The energy content of the breakfast meals will be standardized to ~250 kcal. The meals will include the same fat content but will contain protein sourced predominantly from calcium casein. All ingredients are GRAS listed and approved.; The study participants will be provided with breakfast meals to consume. The energy content of the breakfast meals will be standardized to ~250 kcal. The meals will include the same fat content but will contain protein sourced predominantly from sodium caseinate. All ingredients are GRAS listed and approved.; The study participants will be provided with breakfast meals to consume. The energy content of the breakfast meals will be standardized to ~250 kcal. The meals will include the same fat content but will contain protein sourced predominantly from milk protein caseinate. All ingredients are GRAS listed and approved.; The study participants will be provided with breakfast meals to consume. The energy content of the breakfast meals will be standardized to ~250 kcal. The meals will include the same fat content but will contain protein sourced predominantly from pure protein blend. All ingredients are GRAS listed and approved.; The study participants will be provided with breakfast meals to consume. The energy content of the breakfast meals will be standardized to ~250 kcal. The meals will include the same fat content but will contain protein sourced predominantly from whey protein blend. All ingredients are GRAS listed and approved.; The study participants will be provided with breakfast meals to consume. The energy content of the breakfast meals will be standardized to ~250 kcal. The meals will include the same fat content but will contain protein sourced predominantly from Native Whey Protein Isolate. All ingredients are GRAS listed and approved.; The study participants will be provided with breakfast meals to consume. The energy content of the breakfast meals will be standardized to ~250 kcal. The meals will include the same fat content but will contain protein sourced predominantly from soy protein. All ingredients are GRAS listed and approved.; The study participants will be provided with breakfast meals to consume. The energy content of the breakfast meals will be standardized to ~250 kcal. The meals will include the same fat content but will contain protein sourced predominantly from pea protein. All ingredients are GRAS listed and approved.; The study participants will be provided with breakfast meals to consume. The energy content of the breakfast meals will be standardized to ~250 kcal. The meals will include the same fat content but will contain protein sourced predominantly from native whey: micellar casein (50:50) blend. All ingredients are GRAS listed and approved.; The study participants will be provided with breakfast meals to consume. The energy content of the breakfast meals will be standardized to ~250 kcal. The meals will include the same fat content but will contain predominantly carbohydrates as a control. All ingredients are GRAS listed and approved.
Intervention MeSH terms: Calcium; Caseins
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: tightly-controlled, randomized cross-over design
Masking: Double (Participant, Investigator)
Primary purpose: Prevention