Glycaemic Index Testing

What is the glycaemic index?

The glycaemic index, or GI, is a ranking of carbohydrates in foods based on how they affect blood glucose levels. The lower the GI of the carbohydrate, the slower the carbohydrate is digested and absorbed allowing for slowing increase of glucose in the blood and resulting in lower insulin levels.

What is the OxBCNH testing process?

Once the client contract is signed, participant recruitment begins. Participants are screened before starting every new study. We do a minimum of two reference glucose tests on each participant. Reference glucose tests and participant demographics are updated every 3 months. Blood glucose measurements are taken by trained research assistants every 15 mins for the first hour post food/drink consumption and every 30 mins for the second and third hour. The glycaemic index is calculated with data checked by the RAs and PI on the study. The report is written by the RA and PI and checked by the centre manager. The length of the testing process is unique for each study, the minimum time required to complete a GI study is 4 weeks.

What foods can be tested?

Here at OxBCNH, we test a wide variety of food, drinks and meal supplements. Previously tested products include breakfast cereals, meal supplement drinks, fruit juices and honey/sweeteners.  The best way to check if we can test your product is to contact our centre manager.

What information do I need to provide to begin testing?

In order to begin testing, the client and OxBCNH must both sign a unique contract, detailing start and finish dates, number of participants, type of product and the testing that is being carried out.

What happens once testing is complete?

Once the report is complete, the centre manager will send on the final version to the client. A subsequent virtual meeting can be arranged to address any further queries that clients may have. We ask that clients fill out our Review Box once testing is complete as we are always eager to get feedback and improve our service!

Can our results be published?

If you are interested in publishing results of your study, it is best to contact our centre manager or the principal investigator to get expert advice on how to go about it.

About Organisations

Who is the AfN?

The AfN is an UK registered charity. It is the only register of qualified nutritionists recognised by Public Health England and the NHS. AfN holds the register for qualified nutrition professionals who meet standards for scientifically sound evidence-based nutrition and its use in practice. You can find more information on AfN from their website:

What is the Glycemic Index Foundation?

The Glycemic Index Foundation is a non-profit health promotion charity that primarily provides the community with tools and information about GI. The GI Foundation’s main vision is to present the public with the nutrition and health benefits of including low GI products in the diet. There are many user friendly resources on their website:

What are the ISO guidelines?

The International Organization for Standardization (ISO) is a worldwide federation of national standards bodies. ISO standards are internationally agreed by experts in the specific area. For GI testing, OxBCNH follows ISO 26642:2010 standards. These standards were developed to standardise the method of determining GI of foods for practice and research purposes. More information can be found here.