Effect of a Liquid Tonic Drink on Post-meal Glucose and Insulin Responses

Not Applicable

Recruiting

• Conditions: Overweight or Obese Adults

• Registration Number: NCT07030010
• Lead Sponsor: Australian Catholic University

Brief Summary

A randomised, double blinded, placebo-controlled crossover design clinical trial conducted at the Mary MacKillop Institute for Health Research (MMIHR, Australian Catholic University) for individuals with overweight/ obesity. This study will measure the postprandial glucose and hormone responses to a high-carbohydrate meal with/ without a liquid tonic drink.

Detailed Description

Twenty individuals living with overweight/ obesity will be invited to attend the university laboratories on 2 separate occasions to participate in a postprandial (meal) challenge. Participants will consume the same high-carbohydrate meal on each visit, with or without a liquid tonic drink. This will be a cross-over design study, where participants will consume a placebo drink on the alternate visit. Participants will remain in the laboratory for 3-hours following the meal with a venous cannula in place, and have blood samples taken at regular timepoints. Blood samples will be analysed for glucose and appetite hormones. Participants will also wear a continuous glucose monitor throughout the period which encapsulates both study trials.

Study Timeline

• Status Verified: 2025-06
• Study First Submitted: 2025-06-12
• Study First Submitted QC: 2025-06-12
• Study First Posted: 2025-06-19
• Study Start: 2025-07-08
• Last Update Submitted: 2025-07-18
• Last Update Posted: 2025-07-23
• Primary Completion: 2025-12-19
• Study Completion: 2025-12-19

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 20

Inclusion Criteria

• Aged ≥30-64 years
• Body Mass Index (BMI) of ≥27.0 kg/m2

Exclusion Criteria

• younger than 30 or 65 years or older,
• a BMI less than 27.0 kg/m2,
• have an allergy to any of the components in the plant-based tonic (see section 6),
• pregnant or breastfeeding,
• regularly skipping breakfast (i.e. not consuming breakfast on 5/7 days per week),
• any diagnosed metabolic (e.g. diabetes), endocrine (e.g. hyperthyroidism), gastrointestinal (e.g. Crohn's) or cardiovascular (e.g. heart failure) abnormalities,
• on an energy-restricted diet; significant weight fluctuation in the previous 3 months (>5% body weight),
• high alcohol consumption (>14 units/week) (as per Alcohol Drink Guidelines),
• medication that is used to treat blood glucose,
• unable to attend in person testing sessions, or
• unable or unwilling to provide blood samples.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Primary Outcome Measures

Name	Time	Method
3-hour postprandial glucose incremental area under the curve	3 hours	Venous glucose concentrations measured over the 3 hour period following consumption of the breakfast meal and tonic drink/ placebo, and calculated using the trapezoid method, with T0 concentration as baseline

Secondary Outcome Measures

Name	Time	Method
Venous blood C-peptide responses	3 hours	3-hour postprandial C-peptide responses measured in venous blood as a marker of insulin secretion
3-hour postprandial insulin incremental area under the curve	3-hours	Venous insulin concentrations measured over the 3 hour period following consumption of the breakfast meal and tonic drink/ placebo, and calculated using the trapezoid method, with T0 concentration as baseline
3-hour interstitial postprandial glucose incremental area under the curve	3 hours	The interstitial glucose levels observed for the 3 hours following consumption of the breakfast meal and tonic drink/placebo using continuous glucose monitors
Venous blood insulin to glucagon ratio's at baseline (T0) and 30 minutes (T30)	30 minutes	Ratio of venous blood insulin to glucagon at baseline and 30 minutes (T0, T30) as a marker of hepatic glucose production.
Matsuda index (Marker of whole-body postprandial insulin sensitivity)	3 hours	This marker takes into account the 3- hour postprandial venous blood glucose and insulin measurements observed

Trial Locations

Locations (1)

Australian Catholic University; 🇦🇺 Melbourne, Victoria, Australia