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).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
DOUBLE
Enrollment
35
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.
Purdue University
West Lafayette, Indiana, United States
Appetite Sensations of Hunger
Questionnaires assessing the appetitive sensations of hunger will be completed at specific times throughout each of the the 4-h testing days. The questionnaires contain VAS incorporating a horizontal line rating scale for each response. The questions are worded as "how strong is your feeling of" with anchors of "not all" to "extremely." A summation (area under the curve) will be calculated.
Time frame: 12 testing days across ~6 months
Appetite Sensations of Fullness
Questionnaires assessing the appetitive sensations of fullness will be completed at specific times throughout each of the 4-h testing days. The questionnaires contain VAS incorporating a horizontal line rating scale for each response. The questions are worded as "how strong is your feeling of" with anchors of "not all" to "extremely." A summation (area under the curve) will be calculated.
Time frame: 12 testing days across ~6 months
Appetite Sensations of Desire to Eat
Questionnaires assessing the appetitive sensations of desire to eat will be completed at specific times throughout each of the the 4-h testing days. The questionnaires contain VAS incorporating a horizontal line rating scale for each response. The questions are worded as "how strong is your feeling of" with anchors of "not all" to "extremely." A summation (area under the curve) will be calculated.
Time frame: 12 testing days across ~6 months
Appetite Sensations of Prospective Food Consumption
Questionnaires assessing the appetitive sensations of prospective food consumption will be completed at specific times throughout each of the the 4-h testing days. The questionnaires contain VAS incorporating a horizontal line rating scale for each response. The questions are worded as "how strong is your feeling of" with anchors of "not all" to "extremely." A summation (area under the curve) will be calculated.
Time frame: 12 testing days across ~6 months
Perceived Food Cravings: Sweet
Questionnaires assessing the food cravings will be completed at specific times throughout each of the 4-h testing days. The questionnaires contain VAS incorporating a horizontal line rating scale for each response. The questions are worded as "how strong is your feeling of" with anchors of "not all" to "extremely." A summation (area under the curve) will be calculated.
Time frame: 12 testing days across ~6 months
Perceived Food Cravings: Salty
Questionnaires assessing the food cravings will be completed at specific times throughout each of the the 4-h testing days. The questionnaires contain VAS incorporating a horizontal line rating scale for each response. The questions are worded as "how strong is your feeling of" with anchors of "not all" to "extremely." A summation (area under the curve) will be calculated.
Time frame: 12 testing days across ~6 months
Perceived Food Cravings: Savory-fat
Questionnaires assessing the food cravings will be completed at specific times throughout each of the 4-h testing days. The questionnaires contain VAS incorporating a horizontal line rating scale for each response. The questions are worded as "how strong is your feeling of" with anchors of "not all" to "extremely." A summation (area under the curve) will be calculated.
Time frame: 12 testing days across ~6 months
Perceived Food Cravings: Meat
Questionnaires assessing the food cravings will be completed at specific times throughout the each of the 4-h testing days. The questionnaires contain VAS incorporating a horizontal line rating scale for each response. The questions are worded as "how strong is your feeling of" with anchors of "not all" to "extremely." A summation (area under the curve) will be calculated.
Time frame: 12 testing days across ~6 months
Perceived Breakfast Palatability
Questionnaires assessing the breakfast palatability will be completed at specific times throughout each of the 4-h testing days. The questionnaires contain VAS incorporating a horizontal line rating scale for each response. The questions are worded as "how strong is your feeling of" with anchors of "not all" to "extremely." A summation (area under the curve) will be calculated.
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Time frame: 12 testing days across ~6 months
Perceived Energy: Sleepiness
Questionnaires assessing perceived sleepiness will be completed at specific times throughout each of the 4-h testing days. The questionnaires contain VAS incorporating a horizontal line rating scale for each response. The questions are worded as "how strong is your feeling of" with anchors of "not all" to "extremely." A summation (area under the curve) will be calculated.
Time frame: 12 testing days across ~6 months
Perceived Energy: Energy
Questionnaires assessing perceived energy will be completed at specific times throughout each of the 4-h testing days. The questionnaires contain VAS incorporating a horizontal line rating scale for each response. The questions are worded as "how strong is your feeling of" with anchors of "not all" to "extremely." A summation (area under the curve) will be calculated.
Time frame: 12 testing days across ~6 months
Perceived Energy: Alertness
Questionnaires assessing perceived alertness will be completed at specific times throughout each of the 4-h testing days. The questionnaires contain VAS incorporating a horizontal line rating scale for each response. The questions are worded as "how strong is your feeling of" with anchors of "not all" to "extremely." A summation (area under the curve) will be calculated.
Time frame: 12 testing days across ~6 months
Food Cravings Inventory
Participants will fill out a Food Cravings Inventory (FCI) at 4-h post-breakfast on each testing day. The FCI is a reliable and valid self-report measure of general and specific food cravings including cravings for high fat foods, carbohydrates/starches, sweets, and fast food. The FCI defines a craving as an intense desire to consume a particular food (or food type) that is difficult to resist.
Time frame: 12 testing days across ~6 months
Hormonal Response to Interventions: Plasma Ghrelin
Ten blood samples (4 ml/sample) will be collected throughout each of the the 4-h testing days. The samples will be collected in EDTA test tubes containing pefabloc SC and DPP-IV to reduce protein degradation. Within 10-min of collection, the samples will be centrifuged, and the plasma will be stored at -80°C for future analysis.
Time frame: 12 testing days across ~6 months
Hormonal Response to Interventions: Plasma PYY
Ten blood samples (4 ml/sample) will be collected throughout each of the 4-h testing days. The samples will be collected in EDTA test tubes containing pefabloc SC and DPP-IV to reduce protein degradation. Within 10-min of collection, the samples will be centrifuged, and the plasma will be stored at -80°C for future analysis.
Time frame: 12 testing days across ~6 months
Hormonal Response to Interventions: Plasma GLP-1
Ten blood samples (4 ml/sample) will be collected throughout each of the the 4-h testing days. The samples will be collected in EDTA test tubes containing pefabloc SC and DPP-IV to reduce protein degradation. Within 10-min of collection, the samples will be centrifuged, and the plasma will be stored at -80°C for future analysis.
Time frame: 12 testing days across ~6 months
24-h Energy Intake Dietary Recalls
To assess the participant's total energy content, macronutrient content, macronutrient consumption, and meal patterning, all subjects will complete a dietary recall following each testing day. The study staff will contact the participant the day after each of the testing days and ask questions related to the quantity, type, brand, preparation, and timing of food consumed following the testing day. Total energy content and macronutrient composition will be calculated using nutrition software.
Time frame: 12 testing days across ~6 months
Ad Libitum Breakfast
Free-living energy intake at breakfast will be assessed on day 5, of each testing period, through a meal-specific food packout . The participants will first consume the respective breakfast treatment. Additionally, the participants will be provided with an excess of macronutrient-specific foods to consume, ad libitum for the breakfast time period (30 minutes), after the required, respective breakfast treatment. All food items will be initially weighed and recorded. The participants will be instructed to return all uneaten foods as well as all wrappers and containers from consumed food. Any partially eaten, returned items will be weighed accordingly. Breakfast meal energy and macronutrient content will be assessed from these packouts.
Time frame: 12 testing days across ~6 months