In this study we will study and compare the postprandial metabolic response of 5 snack bar variants, 1 control product and 2 glucose (25g) reference drinks. The study will have a total of 8 test sessions in a non-blinded, crossover design. Online computer software will be used for simple randomization of the sequence of the 8 treatments (http://www.randomizer.org/).The 5 snack bars variants will be similar in macronutrient composition but will differ in the source of carbohydrate, fibre and protein (rice, bamboo, inulin, soy, promitor). They will be compared to a visually similar control product (crokao) that is higher in sugar. The reference drink will be anhydrous glucose (25g) dissolved in 250 ml of water.Study population: 15-20 participants will be recruited from each of the following ethnicities: Chinese, Indian and Caucasian. During the screening session, participants will receive an informed consent form and given ample time to go through it and rectify any queries they have with the researcher. The number of test sessions will be discussed between the researcher and the participants, depending on the volunteer's schedule. If they decide to take part in the study, they will be asked to sign the informed consent form. They will then be asked to complete a screening questionnaire and subsequently baseline measurements including anthropometric measurements, blood pressure, and fasting blood glucose will be collected from each participant in order to determine their eligibility. The screening questionnaire will include demographic, general health details, and physical activity level. This information will be used to determine whether the participant is eligible for the study, as well as to check for any possible confounders that may influence the study outcomes. Anthropometric measurements: Body weight and body composition will be measured using bioelectrical impedance analysis (Tanita scale). Height will be measured using a stadiometer in order to calculate participants' BMI. Waist circumference will be measured at the minimum circumference between the iliac crest and the rib cage and hip circumference will be measured at the maximum protuberance of the buttocks. Blood pressure will be measured using an Omron blood pressure monitor (Model HEM-907) at baseline. Participants will be seated for five minutes before blood pressure is measured. Measurements will be taken in duplicate and the averaged results will be recorded.
Study protocol: The day before a test day, participants will be encouraged to consume their usual diet and avoid alcohol consumption and participating in vigorous exercise. On test days, participants will arrive at the laboratory after an overnight fast of 10 h. Upon arrival, participants will be asked to void, and have their weight and body fat assessed with a Tanita scale. After that, participants will enter the clinical suit and rest for 15 min before a blood catheter is inserted in the antecubital vein of the arm. After the blood catheter is inserted, participants will rest for 15 min, before two baseline blood sample (6 mL) are taken 10 minutes apart (-10 min and 0 min). Immediately after the second sample, participants will be served a test food that has to be consumed within 15 min. Subsequently blood samples (6mL) are obtained at 15, 30, 45, 60, 90,120, 180 and 240min. Appetite sensations (e.g. hunger, fullness, desire-to-eat etc.) will also be measured using questionnaires at similar time points when blood samples are taken. Subjects will be asked to rate their appetite sensations on a 100 mm visual analogue scale (VAS). After each session, the blood catheter will be removed. The participants will leave the laboratory and they will be asked to keep a food diary of what they eat for the remaining day. Participants will return until all test foods are consumed. During the entire test session, the subject will have to stay rested and in the laboratory. Television and a workspace will be provided to the subject.Blood samples will be will analysed for METABOLIC RESPONSE (glucose, insulin, Triglycerides, NEFA, GLP-1 and ghrelin). A 100 uL aliquot of blood during the first blood sample collection (T = -10min) will be obtained from each participant on the first day of treatment (thus only once) for baseline metabolomics profiling.A stool sample from each participant will be obtained to perform the following on the microbiome: DNA extraction, library prep, 16S and shotgun (whole genome) sequencing, and demultiplexing of genomic data. The stool sample will be collected between the screening session and the last test session (time of collection will not influence the sample analysis). The participant will be encouraged to collect the stool sample during one of the sessions at the research centre to eliminate transport of the sample.
