Investigating in Humans the Impact of Training Status on Dietary Consumption With Direct Measurement of Ingestive Behaviour

Energy Intake from Liquid Meal Consumption

Total energy intake (in kilocalories) from consumption of high-carbohydrate, high-sucrose, and high-fat lactose-free milk during each visit. Intake is measured using a drinkometer device that quantifies the exact volume consumed, which is then converted into kilocalories based on the known energy density of each meal type. The unit of measure is kilocalories (kcal).

Time frame: From enrolment to the end of the study participation through four study visits within three months.

Macrostructure of Ingestive Behavior (Rate of Energy Intake)

The rate of energy intake is calculated for each participant during the ingestion of each of the three test stimuli, based on standardized measurements from the drinkometer system. This measure reflects the average caloric intake per second over the course of the test stimulus consumption. Energy intake is determined by the volume of liquid consumed, multiplied by the known caloric density of the test stimulus, and divided by the duration of the ingestion period. The unit of measure is kilocalories per second (kcal/s). This outcome is assessed during the first three study visits, in which a single test stimulus is administered at each visit. It is not measured during the fourth study visit, where all three test stimuli are presented simultaneously.

Time frame: From enrolment to the end of the study participation through three of four study visits within three months

Macrostructure of Ingestive Behavior (Meal Duration)

Meal duration is defined as the total time taken by each participant to consume each of the three test stimuli, measured using the standardized drinkometer system. For each stimulus, the duration is recorded from the initiation of ingestion (first measurable suck) to the completion of consumption (last measurable suck). The unit of measure is seconds (s). This outcome is assessed during the first three study visits, each involving the administration of a single test stimulus. Meal duration is not measured during the fourth study visit, where all three test stimuli are offered to participants simultaneously.

Time frame: From enrolment to the end of the study participation through three of four study visits within three months.

Macrostructure of Ingestive Behavior (Number of Sucks)

The primary outcome is the number of sucks performed by each participant during the ingestion of each of the three test stimuli, as measured using a standardized drinkometer system. A "suck" is defined as a discrete negative pressure event generated by the participant to draw in liquid, as detected by the drinkometer's calibrated weight sensors. For each stimulus, the total number of sucks is recorded as a simple count, with the unit of measure being "number (n)." The outcome is assessed during the first three study visits, each of which features a single test stimulus administered in a standardized fashion. This outcome is not measured during the fourth study visit, in which all three test stimuli are offered simultaneously to the participant.

Time frame: From enrolment to the end of the study participation through three of four study visits within three months.

Microstructure of Ingestive Behavior (Suck Energy Intake)

Suck energy intake is defined as the total amount of energy (in kilocalories) consumed by the participant during each individual suck, measured for each of the three test stimuli using a standardized drinkometer system. For each test stimulus, the total caloric intake is calculated by multiplying the volume of liquid ingested by its caloric density and summing the values across all measured sucks. The unit of measure is kilocalories (kcal). This outcome is assessed during the first three study visits, where each visit involves a single test stimulus. Suck energy intake is not measured during the fourth study visit, in which all three test stimuli are presented to the participant simultaneously.

Time frame: From enrolment to the end of the study participation through three of four study visits within three months.

Microstructure of Ingestive Behavior (Suck Duration)

Suck duration is defined as the time span of each individual suck performed by the participant during the ingestion of each of the three test stimuli, as measured by a standardized drinkometer system. For each test stimulus, the duration of every suck is recorded from the initiation to the completion of the negative pressure event. The unit of measure is seconds (s). This outcome is assessed during the first three study visits, where a single test stimulus is administered at each visit. Suck duration is not measured during the fourth study visit, in which all three test stimuli are presented simultaneously.

Time frame: From enrolment to the end of the study participation through three of four study visits within three months.

Microstructure of Ingestive Behavior (Suck Rate)

Suck rate is defined as the average energy intake of liquid ingested per second during each individual suck, measured for each of the three test stimuli using a standardized drinkometer system. For each test stimulus, the energy intake consumed during each suck is divided by the corresponding suck duration to determine the rate of ingestion for that event. The unit of measure is kilocalories per second (kcal/s). This outcome is assessed during the first three study visits, where a single test stimulus is administered at each visit. Suck rate is not measured during the fourth study visit, in which all three test stimuli are presented simultaneously.

Time frame: From enrolment to the end of the study participation through three of four study visits within three months.

Microstructure of Ingestive Behavior (Suck Maximal Rate)

Suck maximal rate is defined as the highest instantaneous rate of liquid ingestion (in kilocalories per second) achieved during any single suck by the participant for each of the three test stimuli, as measured using a standardized drinkometer system. For each test stimulus, the maximal rate is determined by identifying the suck with the greatest energy intake per unit time among all measured sucks during the ingestion period. The unit of measure is kilocalories per second (kcal/s). This outcome is assessed during the first three study visits, with each visit involving a single test stimulus. Suck maximal rate is not measured during the fourth study visit, where all three test stimuli are presented simultaneously.

Time frame: From enrolment to the end of the study participation through three of four study visits within three months.

Microstructure of Ingestive Behavior (Burst Number)

Burst number is defined as the total count of distinct bursts performed by the participant during the ingestion of each of the three test stimuli, as measured using a standardized drinkometer system. A "burst" is operationally defined as a sequence of successive sucks separated by brief pauses, typically reflecting a rhythmic drinking pattern. For each test stimulus, the number of such bursts is recorded as an integer value. The unit of measure is "number of bursts" (n). This outcome is assessed during the first three study visits, where a single test stimulus is administered at each visit. Burst number is not measured during the fourth study visit, in which all three test stimuli are presented simultaneously.

Time frame: From enrolment to the end of the study participation through three of four study visits within three months.

Microstructure of Ingestive Behavior (Burst Duration)

Burst duration is defined as the total elapsed time of each individual burst performed by the participant during the ingestion of each of the three test stimuli, as measured using a standardized drinkometer system. A "burst" is operationally defined as a sequence of consecutive sucks separated by brief pauses. For each burst, the duration is measured from the onset of the first suck to the end of the last suck within the burst. The unit of measure is seconds (s). This outcome is assessed during the first three study visits, with each visit involving a single test stimulus. Burst duration is not measured during the fourth study visit, in which all three test stimuli are presented simultaneously.

Time frame: From enrolment to the end of the study participation through three of four study visits within three months.

Microstructure of Ingestive Behavior (Burst Energy Intake)

Burst energy intake is defined as the total amount of energy intake (in kilocalories) consumed during each individual burst by the participant, measured for each of the three test stimuli using a standardized drinkometer system. A "burst" is operationally defined as a sequence of consecutive sucks separated by brief pauses. For each burst, the energy intake is calculated by multiplying the volume of liquid ingested within the burst by the energy density of the test stimulus. The unit of measure is kilocalories (kcal). This outcome is assessed during the first three study visits, each involving a single test stimulus. Burst size is not measured during the fourth study visit, in which all three test stimuli are offered simultaneously.

Time frame: From enrolment to the end of the study participation through three of four study visits within three months.

Microstructure of Ingestive Behavior (Burst Rate)

Burst rate is defined as the average rate of energy intake during each individual burst performed by the participant for each of the three test stimuli, as measured using a standardized drinkometer system. For each burst, the total energy intake (in kilocalories) is divided by the duration of the burst (in seconds) to determine the average rate of energy intake for that burst. The unit of measure is kilocalories per second (kcal/s). This outcome is assessed during the first three study visits, each involving a single test stimulus. Burst rate is not measured during the fourth study visit, in which all three test stimuli are offered simultaneously.

Time frame: From enrolment to the end of the study participation through three of four study visits within three months.

Microstructure of Ingestive Behavior (Number of Sucks per Burst)

Number of sucks per burst is defined as the average count of individual sucks occurring within each burst during the ingestion of each of the three test stimuli, as measured using a standardized drinkometer system. A "burst" is operationally defined as a sequence of consecutive sucks separated by brief pauses. For each burst, the total number of sucks is recorded, and the outcome is typically reported as the mean number of sucks per burst. The unit of measure is "number of sucks per burst" (n). This outcome is assessed during the first three study visits, where a single test stimulus is administered at each visit. Number of sucks per burst is not measured during the fourth study visit, in which all three test stimuli are presented simultaneously.

Time frame: From enrolment to the end of the study participation through three of four study visits within three months.

Microstructure of Ingestive Behavior (Inter-Burst Intervals)

Inter-burst interval is defined as the elapsed time between the end of one burst and the onset of the subsequent burst during the ingestion of each of the three test stimuli, as measured using a standardized drinkometer system. A "burst" is operationally defined as a sequence of consecutive sucks separated by brief pauses. The inter-burst interval quantifies the temporal spacing between bursts and is recorded in seconds (s). This outcome is assessed during the first three study visits, each involving a single test stimulus. Inter-burst intervals are not measured during the fourth study visit, in which all three test stimuli are offered simultaneously.

Time frame: From enrolment to the end of the study participation through three of four study visits within three months.

Microstructure of Ingestive Behavior (Inter-Sucks Intervals)

Inter-suck interval is defined as the elapsed time between the end of one suck and the initiation of the subsequent suck during the ingestion of each of the three test stimuli, as measured using a standardized drinkometer system. A "suck" is operationally defined as a discrete negative pressure event corresponding to the drawing in of liquid. The inter-suck interval quantifies the temporal spacing between individual sucks within a burst or throughout the test stimulus consumption, and is recorded in seconds (s). This outcome is assessed during the first three study visits, each involving a single test stimulus. Inter-suck intervals are not measured during the fourth study visit, in which all three test stimuli are presented simultaneously.

Time frame: From enrolment to the end of the study participation through three of four study visits within three months.