Condition category
Nutritional, Metabolic, Endocrine
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Background and study aims
Maintaining a blood sugar concentration of around 4.5-6 mmol/L is important for the body, especially for fuel supply to areas such as the brain. Insulin is the key hormone involved in the regulation of blood sugar, with an increase in insulin causing glucose to be stored by the body’s cells lowering blood sugar levels. Evidence suggests that young people undergo a period of insulin resistance during puberty, where their body does not respond to insulin as effectively and so higher levels of insulin are needed to maintain blood sugar within a healthy range. Evidence also suggest that this response is exaggerated in girls compared to boys and may be affected by maturity. No studies to date have examined how everyday meals which differ in their glycaemic index (GI; a ranking of how a carbohydrate-containing food affects blood sugar levels) are affected by this period of insulin resistance during puberty. The aim of this study is to compare the effects of a high GI (quickly broken down during digestion, increasing blood sugar) breakfast and a low GI (minimal effect on blood sugar levels) breakfast in adolescent girls and boys.

Who can participate?
Healthy children aged 11-14 years.

What does the study involve?
Participants are allocated to eat two breakfasts in a random order, on separate days, 7 days apart. The high GI breakfast consists of cornflakes, milk, toast and margarine. The low GI breakfast consists of muesli, milk and apple. Each breakfast is matched for energy and macro nutrient (carbohydrate, protein and fat) content for each participant so it provides 1.5 g of carbohydrate per kg body mass. On each study visit before eating the breakfast and then 15, 30, 60 and 120 minutes after breakfast, a fingertip blood sample is taken and so that blood sugar and insulin levels can be measured. The results are then compared between boys and girls for the two types of breakfast.

What are the possible benefits and risks of participating?
There are no direct benefits or risks involved with participating.

Where is the study run from?
1. Charnwood College (UK)
2. Market Bosworth High School (UK)

When is the study starting and how long is it expected to run for?
September 2009 to March 2010

Who is funding the study?
Nottingham Trent University (UK)

Who is the main contact?
Dr Simon Cooper

Trial website


Contact information



Primary contact

Dr Simon Cooper


Contact details

Sport Science Department
Nottingham Trent University
Clifton Lane
NG11 8NS
United Kingdom
+44 1158 488059

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Sex differences in adolescents’ glycaemic and insulinaemic responses to high and low glycaemic index breakfasts


Study hypothesis

Girls will display a greater insulinaemic response to high and low glycaemic index meals than boys.

Ethics approval

Loughborough University Ethical Advisory Committee, 01/10/2009, ref: R09-P118

Study design

Randomised cross-over trial

Primary study design


Secondary study design

Randomised cross over trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Glycaemic and insulinaemic responses


Participants are individually, randomly allocated to a trial order using the ‘ABBA’ method. Participants then consumed two breakfasts in the order based upon the allocation process on two separate days spaced 7 days apart.

High GI: Breakfast consists of cornflakes with milk, with white toast and margarine
Low GI: Breakfast consists of muesli with milk and an apple

In both groups, participants are given 15 minutes to consume the breakfasts. Before eating the breakfast and then after 15, 30, 60 and 120 minutes, participants have capillary blood samples taken to test for blood glucose and plasma insulin.

Intervention type



Drug names

Primary outcome measure

1. Blood glucose concentration is measured using the GOD-PAP method using capillary blood samples at baseline and 15, 30, 60 and 120 minutes following the breakfast in each trial condition
2. Plasma insulin concentration is measured using an ELISA assay on capillary blood samples at baseline and 15, 30, 60 and 120 minutes following the breakfast in each trial condition

Secondary outcome measures

Insulin resistance is measured using HOMA (Homeostatic Model Assessment), calculated using the fasting blood glucose and plasma insulin concentrations collected at baseline.

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Aged 11-14 years
2. Healthy

Participant type

Healthy volunteer

Age group




Target number of participants


Participant exclusion criteria

1. Any condition which may make the taking of capillary blood samples problematic
2. Any food allergies or intolerances to the foods provided

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Charnwood College (formerly Garendon High School)
Thorpe Hill
LE11 4SQ
United Kingdom

Trial participating centre

Market Bosworth High School
Station Road, Back Lane
Market Bosworth
CV13 0JT
United Kingdom

Sponsor information


Institute of Youth Sport

Sponsor details

Sir John Beckwith Centre for Sport
Loughborough University
LE11 3TU
United Kingdom

Sponsor type




Funder type


Funder name

Nottingham Trent University

Alternative name(s)


Funding Body Type

private sector organisation

Funding Body Subtype

Universities (academic only)


United Kingdom

Results and Publications

Publication and dissemination plan

Planned publication of the findings of the study in a scientific journal, with a submission expected in September 2016.

IPD Sharing plan:
One of the conditions of the ethical committee approval was that individual level data will not be made available due to the ethical considerations of working with young people. Therefore, this data cannot be made widely available.

Intention to publish date


Participant level data

Not expected to be available

Basic results (scientific)

Publication list

2017 results in

Publication citations

Additional files

Editorial Notes

18/01/2017: The publication reference has been added.