Glycaemic Responses to Carbohydrate-rich Meals (GlyCarb)

NCT05317429 | Enrolling By Invitation

• 1 other identifier: QIB07/2020
• Study Type: interventional
• Target: 25
• Locations: 1 country
• Sites: 1

Brief Summary

Carbohydrate-rich foods such as potatoes, bread, rice, pasta, breakfast cereals, biscuits and other snacks are a major component of the human diet. The effect of different carbohydrate-rich foods on blood sugar (glucose) levels after a meal varies between foods. This is relevant to health because studies have shown that regular intake of carbohydrate foods that cause large increases in blood glucose levels after ingestion can be detrimental to metabolic health. The aim of the GlyCarb study is to investigate how food structure influences postprandial glycaemic responses to carbohydrate foods. This will be achieved through a series of acute postprandial studies (up to 5 studies), wherein healthy participants within each postprandial study consume a pair of carbohydrate-rich test meals while wearing a continuous glucose monitoring system (CGM). Each postprandial study will use the same GlyCarb Remote standard protocol, where a randomised cross-over design is used to measure the glycaemic response to two carbohydrate-rich test meals, one "test" and one "control". Both meals will be matched by carbohydrate content, contain similar ingredients and have a similar physical appearance, but will differ in one key food property (e.g., altered food structure) to test its effect on postprandial glycaemia. In each postprandial study, habitual dietary intake and body composition will be captured at baseline as part of the participant characterisation. Participants will consume two different carbohydrate-rich test meals twice, on separate occasions, in a randomly allocated order over a 10 to 14-day period of continuous glucose monitoring. Data from the continuous glucose monitors will be used to assess the postprandial glycaemic response to each carbohydrate food. The participants will be required to complete brief questionnaires designed to evaluate differences in palatability (taste, texture, portion size) and satiety amongst test meals. Study participant feedback will be requested at the end of the study and used to assess and improve future study procedures. The GlyCarb study will enable new understanding of how food properties influence glycaemic responses to different types of carbohydrate foods. Ultimately, the findings will inform the rational design or reformulation of food products and diets to support a healthy glucose metabolism.

Conditions

Glycaemia

Keywords

Carbohydrates; Starch

Outcome Measures

Primary Outcomes (1)

• Fasting and postprandial glucose levels measured in interstitial fluid

  Maximum rise in glucose concentration from fasted levels (iCmax)

  0-4 hours after the test meal

Secondary Outcomes (11)

• Glycaemic response indicators

  2 to 4 hours after the test meal

• Glycaemic response indicators

  2 to 4 hours after the test meal

• Glycaemic response indicators

  2 to 4 hours after the test meal

• Glycaemic response indicators

  2 to 4 hours after the test meal

• Glycaemic response indicators

  2 to 4 hours after the test meal

Other Outcomes (4)

• BMI

  Baseline

• Body composition

  Baseline

• Body composition

  Baseline

Study Arms (2)

Treatment

EXPERIMENTAL

Carbohydrate-rich meal

Other: A meal delivering 75 g of carbohydrate

Control

ACTIVE COMPARATOR

Carbohydrate-rich meal

Other: A meal delivering 75 g of carbohydrate

Interventions

A meal delivering 75 g of carbohydrate OTHER

The nature of the test meal will depend upon the research question being addressed and it is anticipated that the test meals may include (but are not limited to) the following: (i) Re-structured, enriched, and/or reformulated or non-conventionally processed food products (ii) Model food matrices with different structures or types of carbohydrate e.g. soups with different viscosity.

Control; Treatment

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Men and women ≥ 18 years of age
• Have access to/own a smartphone or tablet or computer and are willing to use this with apps needed for the study
• BMI between 18 and 30 kg/m2 (calculated from self-reported height and weight)
• Fasted HbA1C \< 42 mmol/mol (6.0%)
• Willing to consume study foods (study foods and ingredients are discussed during the study talk)

You may not qualify if:

• Smokers of tobacco-based cigarettes or electronic cigarettes (or stopped smoking less than 6 months ago)
• Gastro-intestinal disease/disorders e.g., Crohn's disease/ulcerative colitis
• Other medical conditions that are judged to affect the study outcome or which may compromise the well-being of the participant e.g., active cancer, haemophilia. This will be assessed on a case-by-case basis.
• Type 1 diabetes or insulin-dependent or non-insulin-dependent type 2 diabetes
• Active infection with COVID-19, unless they are willing to postpone the screening until after the end of the self-isolation period (10 days from test or symptoms).
• Prescribed and non-prescribed medications that may affect the study outcome or which may compromise the well-being of the participant e.g., warfarin, proton-pump inhibitors. This will be assessed on a case by-case-basis.
• Dietary supplements that are judged to affect the study outcome unless the participant is willing to discontinue them for 4 weeks preceding the start of the study and for the duration of the study. This will be assessed on a case-by-case basis and includes protein supplements (shakes) or supplements that are not taken on a regular basis (on and off), particularly those containing ascorbic acid which may affect glucose readings.
• Any known allergy, intolerance, or sensitivity to any food products oradhesives (for CGM application).
• Those following a restrictive diet that may affect the study outcome (e.g., 5:2 diet) unless they are willing to suspend the diet for the duration of the study.
• Women who are, or have been pregnant, within the last 12 months or who are breast-feeding
• Parallel participation in another research project that involves dietary intervention.
• Any person related to or living with any member of the study team.
• Those who are part of the line manager/supervisory team of the Chief Investigator
• Lack of capacity to provide written informed consent.
• Clinical eligibility test results deemed by the CRF medical advisor to be indicative of a health problem which may compromise the well-being of the participant or which could affect the study outcome.

Sponsors & Collaborators

• Quadram Institute Bioscience: lead
• Norfolk and Norwich University Hospitals NHS Foundation Trust: collaborator

Study Sites (1)

Quadram Institute

Norwich, Norfolk, NR4 7UQ, United Kingdom

Location

MeSH Terms

Interventions

Carbohydrates

Study Officials

• Cathrina Edwards, PhD

  Quadram Institute Bioscience

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: Blinding will be conducted by a member of staff who is independent of the study team. For all studies, an effort will be made to blind the research team and study participants to the test and reference meals. Whilst we recognize that this approach is 'gold standard' it may not be possible in all circumstances, for example due to the different appearance of some food products.
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Randomised crossover study

Study Record Dates

• First Submitted: February 16, 2022
• First Posted: April 7, 2022
• Study Start: February 14, 2022
• Primary Completion (Estimated): March 31, 2028
• Study Completion (Estimated): June 30, 2028
• Last Updated: July 24, 2025

Record last verified: 2025-07

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, CSR
• Time Frame: Data will be available after publication in scientific journal within 18 months of study completion
• Access Criteria: Data access will be reviewed by the study team

Locations

GB (1)