Participant information

Participant information

Objectives of the project

  • Confirm that individuals respond differently to food, i.e, the blood sugar level after the same food or beverage consumption varies between different individuals.
  • Confirm that the variations in glycemic responses are associated with diet, physical activity, sleep, lifestyle and microbiome composition. We will also investigate if glycemic response variations are observed along the menstrual cycle.
  • Build an algorithm that will predict the blood sugar level as a function of the individual and the foods consumed. Later on, this algorithm should provide personalised meals recommendations.
  • Evaluate the ability of MyFoodRepo app to track individual dietary intake accurately and over extended periods of time.
  • Introduce the public to the challenges in scientific research and personalized nutrition.
  • Evaluate whether this project can be scaled up in Switzerland or abroad.

Participants able to participate

If you are interested in the study, you can choose to participate in one of the three cohorts. The differences are the following:

  • Basic (B) cohort:
    • We will cover the cost of the study material.
    • After registration, we will randomly select participants to balance the distribution of participants according to gender, age, weight and height.
    • You will have to track your dietary intake with the app during three days before being enrolled.
    • You will have to consume standardized breakfast from the second to the seventh day.
  • C cohort (for women only):
    • You will have to follow the same procedure as the participants of the basic cohort.
    • You will measure your body temperatures and track your menstrual cycles symptoms for three months.
    • You will continue to track your dietary intake, physical activity and glucose level for an additional two weeks.

Important: if you have a BMI (Body Mass Index) below 18.5 or a lean musculature (for example, if you are an elite athlete), these are not exclusion criteria, but we do not recommend you participate. The filament of the glucose sensor could reach your muscle, which is not dangerous, but on the one hand is painful and on the other hand, distorts the data. If necessary, calculate your BMI here.

Select the cohort you're interested in and check all boxes that apply to you to find out if you're eligible.

B Cohort

C Cohort

Do any of the following statements apply to you?

General information on the project

For information on the scientific background of the project, please look at the Science behind the project. To understand who is behind the project, please look at the team.

The project is entirely coordinated digitally via the website. This means that no face-to-face interviews or medical appointments will be organized. All instructions will be conveyed by the website, emails and text messages.

The project is carried out in compliance with the requirements of Swiss legislation. We also comply with the internationally approved guidelines. The Geneva ethics commission has reviewed and authorized the project. A description of the study can also be found on the website of the Federal Office of Public Health (number SNCTP000002833) and the platform

Study procedure for the participants

All necessary information will be provided on this website at the appropriate time.

Stages Details Duration
Short questionnaire
  • Complete form to provide your age (date of birth), sex, height and weight.
Approx. 5 mins
Test MyFoodRepo app.
  • Take photos of your meals and snacks with MyFoodRepo for three days.
3 days
Preparation for the tracking weeks
  • Order the study material
  • Complete some questionnaires.
  • Read the instructions and indicate your study choice.
Approx. 1h 30 min.
Stool sample collection
  • Collect a stool sample in the tube and ship it back to EPFL in the pre-stamped envelope received with the study material (the material needed will be provided).
Approx. 15 min.
Tracking weeks

  • During 14 days, you will have to track:
    • Your dietary intake with MyFoodRepo
    • Your physical activity and sleep.
    • Your glucose levels by wearing a FreeStyle Libre sensor. You will have to scan your sensor with your smartphone: within 5 minutes after waking up, every 8 hours during the day and within 5 minutes before going to sleep.
    • C cohort only: Measure your body temperature every morning and log your menstrual-related observations in an app.
14 days
Standardized breakfast
  • The first day of the tracking weeks, buy the foods indicated in the shopping list (see below).
  • From the second to the seventh day, you will have to consume standardized breakfasts, following the instructions below:
    • Consume the standardized breakfast immediately after waking up.
    • Consume the entire meal without any modifications, and without eating anything else for two hours.
    • Refrain from performing strenuous physical activities before and for two hours following standardized meal consumption.
  • For the others meals during the two weeks, follow your daily routine and dietary habits.
7 days
Additional tracking weeks

Only for the participants of the C cohort

  • You will have to continue tracking your dietary intake, physical activity, menstrual cycle and blood glucose measurements for an additional two weeks so that we can study the glycemic response throughout the menstrual cycle. After two weeks, you will have to remove the first sensor, and replace it with a new one. You will receive both sensors with the material to participate in the study.
  • Eat standardized breakfasts a second time.
  • Continue to track your menstrual cycle during at least two months.
14 days and 2 months
End of data collection
  • Fill out the feedback questionnaire.

Approx. 15 min.
Personalized feedback
  • You will receive personalized feedback of your participation in the project. For more info, see Benefits for participants below.
Within 6 months of completing study

Diet plan

Day(s) Non-restricted Non-dairy Non-gluten Non-dairy/gluten
2 & 3 110 g white bread 110 g white gluten-free bread
4 & 5 110 g white bread, 30 g butter 55 g white bread, 50 g dark chocolate 110 g gluten-free white bread, 30 g butter 55 g gluten-free white bread, 50 g dark chocolate
6 & 7 glucose drink (50g)

You will not be allowed to add anything to these meals (for example, no jam on the bread), and will not be allowed to eat anything else for two hours after these six breakfasts. For the others meals during the two weeks, follow your daily routine and dietary habits.
Cohort C participants will have to eat these six breakfasts twice.

Benefits for participants

  • You will receive a detailed view of your glycemic level over two weeks, it could help you to understand how your glucose levels respond to food, exercise, and sleep.
  • Within a maximum of around six months after the study enrollment, you will receive feedback containing :
    • Some statistics on your food consumption (e.g., the proportion of each food group consumed or the average number of calories per day).
    • A score for each meal consumed during the tracking weeks representing the effect of each meal on your interstitial glucose levels.
    • A detailed report of your gut microbiota composition.
    • General feedback on the project.
  • The findings of this project could potentially be beneficial to people with health issues related to diet (for example, for the people suffering diabetes).
  • You will be acquainted with scientific research and you will understand the challenges of personalized nutrition.
  • For the participants of the C cohort: you will have a comprehensive view of your menstrual cycle and your glucose level variation.

Rights of participants

You should participate in this study only at your own will. If you choose not to participate or if you choose to participate and reconsider your decision during the course of the study, you will not have to justify your withdrawal. You can ask your questions using the contact form.

Obligations of participants

As a participant in the study, you will be expected to follow the instructions that will be given to you and comply with the study plan.


The study does not pose any major risk. The data will be collected using non-invasive methods, except for the FreeStyle Libre sensor used to measure the glucose level (with an applicator, you will have to insert a very thin filament beneath your skin surface). The procedure meets all safety requirements. The glucose sensor can provoke a skin allergic reaction. In these cases, you will have to remove it, contact the sensor provider and interrupt the study.

For women of reproductive age

If you discover that you are pregnant during the study, you should inform the investigator immediately. You will then have to interrupt the study.

Fortuitous discoveries

As there are no visits to the physician scheduled during the study, we cannot commit to providing diagnoses related to your health. However, depending on your individual needs, you will be able to contact a doctor associated with the research team of this project.

Confidentiality and data policy

Project data is handled with the utmost discretion and will be only accessible to authorized staff who need the data to complete their duties within the scope of the research project. Generation, transmission, storage and analysis of health-related data and the storage of biological samples within this project strictly follow the current Swiss legal requirements for data protection and are performed according to the Swiss Ordinance on Clinical Trials in Human Research (ClinO), Art 5.

Coding will safeguard participants' confidentiality. This means that your sensitive data will not be directly linked to your identifiable data (name, email, address, date of birth, etc), but they will be associated to identification code numbers (de-identification). Only the main investigator will have access to the coding key to link your sensitive data to your identifiable participant data. In case of a publication in a scientific journal, the aggregated data will not be attributable to you as a person. Your name will never appear in an open or public document. Occasionally, scientific journals require the raw data. In this case, the individual data transmitted will always be coded and therefore it will not be possible to identify you as a person.

You will have the choice to sign a separate consent form specifically for the reuse of your data. If you accept, your data and biological samples may subsequently be used in other research projects or sent for analysis to another biobank, in Switzerland or abroad (re-use) for use in other research projects. This biobank would have to comply with the same standards and requirements as the biobank of this project.

The project may be inspected by the ethics committee responsible for the initial control and authorization of the project. In this case, the project investigator may need to communicate your data for the inspections.


You can withdraw from the study at any time if you wish. Health-related data and biological material collected up to that time will be anonymized and still be analyzed so as not to compromise the value of the study as a whole. In addition, you should withdraw from the study for the following reasons:

  • If you are unable to follow the instructions during the tracking weeks.
  • If you have an allergic reaction to the FreeStyle Libre sensor.

In case of withdrawal, the biological material, i.e. the DNA extracted from the stool sample, will be permanently destroyed and your health-related data anonymized. It will, therefore, be impossible to trace the origin of the data and samples.


If you are participating in this project, you will not be paid. The participants’ benefits are given in the above section.

Reparation of damages

EPFL is responsible for any damage you may suffer in relation to research activities. The conditions and procedure are laid down by law. Any injury or damage due to the participation in the above-mentioned research project and for which the responsibility of the EPFL can be established is covered by the general liability insurance of EPFL (insurance policy no. 501 402430.002 of La Mobilière Assurances), in accordance with the terms and conditions of the insurance. In any case, it is your responsibility to have sufficient coverage in case of illness and accident. In case of doubt, you can contact us.

Project financing

The project is financed mainly by the Kristian Gerhard Jebsen foundation. This foundation aims to enhance the well-being of people and promote human and social development, through support of grantees in the areas of health, education, science, culture and environment, in Switzerland and abroad. No food-related or pharmaceutical-related industry is financing this study.


In case of doubt, concerns or emergency during or after the project, you can contact us at any time.

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