Dietary HabitsSuHeGuideNCT05253547
Dietary Intervention Study on Food Based Dietary Guidelines for Sustainable and Healthy Lifestyles
A study testing Healthy climate-friendly dietary guidelines and Healthy dietary guidelines in people with Dietary Habits and Healthy Diet, run by University College Dublin at 3 sites in 2 countries.
Trial summary
The aim of the study is to provide proof of the effectiveness, acceptability, healthfulness and nutritional adequacy of dietary guidelines to reduce greenhouse gas emissions. The study will compare the effect of dietary advice based on 1) healthy climate-friendly dietary guidelines (intervention group) or 2) standard… Read more about this study
- Who is it for?
- Ages 18 to 64 yearsHealthy volunteers can take part
- Conditions the study is for
- Dietary Habits, Healthy Diet, Healthy Nutrition
- What is being tested?
- Healthy climate-friendly dietary guidelines and Healthy dietary guidelines
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 355 participants
- Where
- 3 sitesin 2 countries
- Study dates
- 21 Mar 2022to 1 Jun 2023
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 64 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Provide written informed consent
- Be a healthy adult between the ages of 18-64 years old
- Consume a diet associated with moderate-high greenhouse gas emissions
- Be in good general health
Who cannot join
- Are pregnant, lactating or planning to become pregnant
- Are following a medically prescribed diet
- Have a diagnosis of an acute or chronic medical condition that could interfere with the outcomes of the study. Such diagnoses include (but are not limited to) cardiovascular disease, diabetes mellitus, inflammatory bowel disease, cancers (within the last 5 years), etc.
- Are immunocompromised or have a suspected immunodeficiency
- Have excessive alcohol intake (>28 units per week)
- Have a known food allergy
Show all 9Show fewer
- Regularly consume a single high-dose vitamin or mineral supplement
- Are participating in another research study
- Are unable to read, write or understand English.
Trial locations and contacts
3 sites in 2 countries.
3 sites in 2 countries
Ireland2 sites
University College Cork
Cork
University College Dublin
Dublin, Dublin 4
About this study
The aim of the study is to provide proof of the effectiveness, acceptability, healthfulness and nutritional adequacy of dietary guidelines to reduce greenhouse gas emissions. The study will compare the effect of dietary advice based on 1) healthy climate-friendly dietary guidelines (intervention group) or 2) standard healthy dietary guidelines (control) on greenhouse gas emissions associated with dietary intake over 12 weeks.
Read the detailed description
A randomised, parallel controlled trial will recruit n=360 healthy adults (age 18-64) across three research centres. After successful screening and receiving informed consent, participants will be randomised into the intervention or the control group for the duration of the 12-week trial described in detail in the text and figure below. The intervention group will receive dietary advice based on climate friendly eating recommendations. The control group will receive dietary recommendations based on Healthy Ireland's Healthy Eating Guidelines and Food Pyramid (FSAI, 2019).
Prior to their first onsite visit, participants will be asked to complete a Health and Lifestyle questionnaire and dietary assessment. The dietary assessment will include
- 3 online 24-hour recalls (2 non-consecutive weekdays and 1 weekend day) (via web-based dietary recall tool, Foodbook24)
- a food frequency questionnaire (Foodbook24)
Baseline, Visit 1 (Week 0): We will collect blood and urine samples from participants and record anthropometric measurements. Participants will be asked to complete a Stage of Change questionnaire to assess their openness to a diet change. All participants will complete a Food Waste Questionnaire at baseline for later comparison at endpoint. At the end of Visit 1 participants will receive a personalised feedback report and advice from nutritionists based on their habitual diet.
Week 6: Participants will be asked to complete a second dietary assessment during week 6. 3 24-hour recalls and a food frequency questionnaire will be hosted on Foodbook24, a web-based dietary recall tool.
Week 11: Before attending endpoint onsite visit, participants will complete a final dietary assessment. The same assessment as Pre-baseline and Week 6 will be used.
Endpoint, Visit 2 (Week 12): At the end of 12 weeks, participants will be invited back for a follow-up assessment. Blood and urine samples and anthropometrics will be collected/recorded. Participants will complete the Stage of Change questionnaire and Food Waste questionnaire. A Tolerance questionnaire will be administered to see how willing participants would be to continue with their prescribed diet.
- Being tested
- Healthy climate-friendly dietary guidelines, Healthy dietary guidelines
- Keywords
- Sustainable diets, Greenhouse gas emissions, Climate-friendly, Personalized nutrition
- Medical subject headings
- Feeding Behavior
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Healthy climate-friendly dietary guidelinesBehavioural
Personalised climate-friendly healthy dietary recommendations
Healthy dietary guidelinesBehavioural
Personalised healthy dietary recommendations
| Study group | Role | What they receive |
|---|---|---|
| Healthy climate-friendly dietary guidelines | Experimental | Personalised healthy dietary recommendations aimed at reducing diet-related greenhouse gas emissions Receives: Behavioral: Healthy climate-friendly dietary guidelines |
| Healthy eating guidelines | Active comparator | Personalised healthy dietary recommendations based on Ireland's Healthy Eating Guidelines Receives: Behavioral: Healthy dietary guidelines |
What is being measured
The primary outcome is the main question the study is designed to answer.
Diet-related greenhouse gas emissions reported as kilograms of carbon dioxide equivalents per day
Participants will record their diet at baseline (habitual diet) and endpoint (intervention diet) using an online 24-hour recall method. Diet-related greenhouse gas emissions will be estimated using food, nutrient and food-related greenhouse gas emissions databases (measured as kilograms of carbon dioxide equivalents). The primary outcome measure is the change in diet-related greenhouse gas emissions (kgCO2-eq/day) as a result of the intervention diet.
Measured: 12 weeks
Secondary outcomes (6)
Calcium intake (milligrams per day)
Calcium intake will be calculated using dietary intake records (3x 24-hour recalls) at baseline and endpoint (intervention diet). The secondary outcome measure is the change in calcium intake (mg/day) as a result of the intervention diet.
Measured: 12 weeks
Iron intake (milligrams per day)
Iron intake will be calculated from dietary intake records (3x 24-hour recalls) at baseline and endpoint (intervention diet). The secondary outcome measure is the change in iron intake (mg/day) as a result of the intervention diet.
Measured: 12 weeks
Urinary iodine (micrograms per liter)
Participants will provide urine samples at baseline (Week 0) and endpoint (Week 12). Urinary iodine concentrations (ug/L) will be measured. The secondary outcome measure is the change in urinary iodine as a result of the intervention diet.
Measured: 12 weeks
Serum vitamin D status (25(OH)D nanomole per liter)
Participants will provide blood samples at baseline (Week 0) and endpoint (Week 12). 25(OH)D will be measured (nmol/L) as a marker of vitamin D status. The secondary outcome measure is the change in vitamin D as a result of the intervention diet.
Measured: 12 weeks
Serum lipids (milimoles per liter)
Participants will provide blood samples at baseline (Week 0) and endpoint (Week 12). Serum lipids, including total cholesterol, HDL cholesterol and triglycerides (mmol/L) will be measured. The secondary outcome measure is the change in lipid profile as a result of the intervention diet.
Measured: 12 weeks
Fasting glucose (milimoles per liter)
Participants will provide blood samples at baseline (Week 0) and endpoint (Week 12). Fasting blood glucose will be measured (mmol/L). The secondary outcome measure is the change in fasting glucose as a result of the intervention diet.
Measured: 12 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Feb 2022
- Study start21 Mar 2022
- Primary completion1 Jun 2023
- Study completion1 Jun 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (4)Papers the sponsor has linked to this study.
- Other trials for Dietary HabitsStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Parallel randomized control trial
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 355 participants (actual)
Sponsor and investigators
- Lead sponsor
- University College Dublin
- Sponsor type
- University, hospital or other
- Collaborators
- Teagasc, University College Cork, Queen's University, Belfast
- Responsible party
- Principal investigator, Aifric O'Sullivan, University College Dublin
- Investigators
- Aifric O'Sullivan, PhD, Principal investigator, University College Dublin
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05253547
- Sponsor's protocol ID
- LS-21-51-Davies-OSullivan
- Acronym
- SuHeGuide
- Status last verified
- Oct 2023
- First submitted
- 8 Feb 2022
- Last updated
- 4 Oct 2023
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: At the start of the study each participant will have a study code assigned to them. All of the data from the trials will be stored using these unique study codes. A file will be set up which will be stored in a location separate to the study data. This file will contain a list which will link each participants contact details to the corresponding ID code. All stored information will be encrypted and protected by a password that only the researcher and PI will know.
Publications
Davies KP, Gibney ER, Leonard UM, Lindberg L, Woodside JV, Kiely ME, Nugent AP, Arranz E, Conway MC, McCarthy SN, O'Sullivan AM. Metabolic Phenotyping Identifies Responders to Sustainable Healthy Diets: Analysis from the MyPlanetDiet Randomized Controlled Trial. Curr Dev Nutr. 2026 Aug 10;10(9):109510. doi: 10.1016/j.cdnut.2026.109510. eCollection 2026 Sep.
PubMed 42733507Davies KP, Gibney ER, Leonard UM, Lindberg L, Woodside JV, Kiely ME, Nugent AP, Arranz E, Conway MC, McCarthy SN, O'Sullivan AM. Sustainable diets reduce diet-related greenhouse gas emissions and improve diet quality: results from the MyPlanetDiet randomized controlled trial. Am J Clin Nutr. 2025 Oct;122(4):962-971. doi: 10.1016/j.ajcnut.2025.05.015. Epub 2025 Aug 26.
PubMed 41043876Leonard UM, Davies KP, Lindberg L, Woodside JV, Nugent AP, O'Sullivan AM, Gibney ER, McCarthy SN, Arranz E, Kiely ME. Impact of sustainable diets on micronutrient intakes and status: outcomes of the MyPlanetDiet randomized controlled trial. Am J Clin Nutr. 2025 Nov;122(5):1275-1288. doi: 10.1016/j.ajcnut.2025.09.009. Epub 2025 Sep 8.
PubMed 40930463Davies KP, Gibney ER, Leonard UM, Lindberg L, Woodside JV, Kiely ME, Nugent AP, Arranz E, Conway MC, McCarthy SN, O'Sullivan AM. Developing and testing personalised nutrition feedback for more sustainable healthy diets: the MyPlanetDiet randomised controlled trial protocol. Eur J Nutr. 2024 Oct;63(7):2681-2696. doi: 10.1007/s00394-024-03457-0. Epub 2024 Jul 6.
PubMed 38970665
Study at a glance
From the registry record, last updated by the sponsor on 4 Oct 2023. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Dietary Intervention Study on Food Based Dietary Guidelines for Sustainable and Healthy Lifestyles
- ClinicalTrials.gov ID
- NCT05253547
- Acronym / sponsor ID
- SuHeGuide / LS-21-51-Davies-OSullivan
- Keywords
- Sustainable diets, Greenhouse gas emissions, Climate-friendly, Personalized nutrition
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 355 participants (actual)
- Lead sponsor
- University College DublinUniversity, hospital or other
- Collaborators
- Teagasc, University College Cork, Queen's University, Belfast
- Study start
- 21 Mar 2022 (actual)
- Primary completion
- 1 Jun 2023 (actual)
- Study completion
- 1 Jun 2023 (actual)
- First posted
- 23 Feb 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aim of the study is to provide proof of the effectiveness, acceptability, healthfulness and nutritional adequacy of dietary guidelines to reduce greenhouse gas emissions. The study will compare the effect of dietary advice based on 1) healthy climate-friendly dietary guidelines (intervention group) or 2) standard healthy dietary guidelines (control) on greenhouse gas emissions associated with dietary intake over 12 weeks.
Detailed description
A randomised, parallel controlled trial will recruit n=360 healthy adults (age 18-64) across three research centres. After successful screening and receiving informed consent, participants will be randomised into the intervention or the control group for the duration of the 12-week trial described in detail in the text and figure below. The intervention group will receive dietary advice based on climate friendly eating recommendations. The control group will receive dietary recommendations based on Healthy Ireland's Healthy Eating Guidelines and Food Pyramid (FSAI, 2019).
Prior to their first onsite visit, participants will be asked to complete a Health and Lifestyle questionnaire and dietary assessment. The dietary assessment will include
- 3 online 24-hour recalls (2 non-consecutive weekdays and 1 weekend day) (via web-based dietary recall tool, Foodbook24)
- a food frequency questionnaire (Foodbook24)
Baseline, Visit 1 (Week 0): We will collect blood and urine samples from participants and record anthropometric measurements. Participants will be asked to complete a Stage of Change questionnaire to assess their openness to a diet change. All participants will complete a Food Waste Questionnaire at baseline for later comparison at endpoint. At the end of Visit 1 participants will receive a personalised feedback report and advice from nutritionists based on their habitual diet.
Week 6: Participants will be asked to complete a second dietary assessment during week 6. 3 24-hour recalls and a food frequency questionnaire will be hosted on Foodbook24, a web-based dietary recall tool.
Week 11: Before attending endpoint onsite visit, participants will complete a final dietary assessment. The same assessment as Pre-baseline and Week 6 will be used.
Endpoint, Visit 2 (Week 12): At the end of 12 weeks, participants will be invited back for a follow-up assessment. Blood and urine samples and anthropometrics will be collected/recorded. Participants will complete the Stage of Change questionnaire and Food Waste questionnaire. A Tolerance questionnaire will be administered to see how willing participants would be to continue with their prescribed diet.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
- Model description
- Parallel randomized control trial
| Arm | Type | Receives |
|---|---|---|
| Healthy climate-friendly dietary guidelines | Experimental | Behavioral: Healthy climate-friendly dietary guidelinesPersonalised healthy dietary recommendations aimed at reducing diet-related greenhouse gas emissions |
| Healthy eating guidelines | Active comparator | Behavioral: Healthy dietary guidelinesPersonalised healthy dietary recommendations based on Ireland's Healthy Eating Guidelines |
Who may qualify
- Ages
- 18 to 64 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Provide written informed consent
- Be a healthy adult between the ages of 18-64 years old
- Consume a diet associated with moderate-high greenhouse gas emissions
- Be in good general health
Key exclusion criteria (9 listed)
- Are pregnant, lactating or planning to become pregnant
- Are following a medically prescribed diet
- Have a diagnosis of an acute or chronic medical condition that could interfere with the outcomes of the study. Such diagnoses include (but are not limited to) cardiovascular disease, diabetes mellitus, inflammatory bowel disease, cancers (within the last 5 years), etc.
- Are immunocompromised or have a suspected immunodeficiency
- Have excessive alcohol intake (>28 units per week)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Healthy climate-friendly dietary guidelinesPersonalised climate-friendly healthy dietary recommendations | Behavioural | Healthy climate-friendly dietary guidelines |
| Healthy dietary guidelinesPersonalised healthy dietary recommendations | Behavioural | Healthy eating guidelines |
Primary outcome
Diet-related greenhouse gas emissions reported as kilograms of carbon dioxide equivalents per day
Time frame: 12 weeks
Participants will record their diet at baseline (habitual diet) and endpoint (intervention diet) using an online 24-hour recall method. Diet-related greenhouse gas emissions will be estimated using food, nutrient and food-related greenhouse gas emissions databases (measured as kilograms of carbon dioxide equivalents). The primary outcome measure is the change in diet-related greenhouse gas emissions (kgCO2-eq/day) as a result of the intervention diet.
6 secondary outcomes
Calcium intake (milligrams per day)
Time frame: 12 weeks
Iron intake (milligrams per day)
Time frame: 12 weeks
Urinary iodine (micrograms per liter)
Time frame: 12 weeks
Serum vitamin D status (25(OH)D nanomole per liter)
Time frame: 12 weeks
Serum lipids (milimoles per liter)
Time frame: 12 weeks
Fasting glucose (milimoles per liter)
Time frame: 12 weeks
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Oct 2023.
- Derived from this study: PubMed 42733507Davies KP, Gibney ER, Leonard UM, Lindberg L, Woodside JV, Kiely ME, Nugent AP, Arranz E, Conway MC, McCarthy SN, O'Sullivan AM. Metabolic Phenotyping Identifies Responders to Sustainable Healthy Diets: Analysis from the MyPlanetDiet Randomized Controlled Trial. Curr Dev Nutr. 2026 Aug 10;10(9):109510. doi: 10.1016/j.cdnut.2026.109510. eCollection 2026 Sep.
- Derived from this study: PubMed 41043876Davies KP, Gibney ER, Leonard UM, Lindberg L, Woodside JV, Kiely ME, Nugent AP, Arranz E, Conway MC, McCarthy SN, O'Sullivan AM. Sustainable diets reduce diet-related greenhouse gas emissions and improve diet quality: results from the MyPlanetDiet randomized controlled trial. Am J Clin Nutr. 2025 Oct;122(4):962-971. doi: 10.1016/j.ajcnut.2025.05.015. Epub 2025 Aug 26.
- Derived from this study: PubMed 40930463Leonard UM, Davies KP, Lindberg L, Woodside JV, Nugent AP, O'Sullivan AM, Gibney ER, McCarthy SN, Arranz E, Kiely ME. Impact of sustainable diets on micronutrient intakes and status: outcomes of the MyPlanetDiet randomized controlled trial. Am J Clin Nutr. 2025 Nov;122(5):1275-1288. doi: 10.1016/j.ajcnut.2025.09.009. Epub 2025 Sep 8.
- Derived from this study: PubMed 38970665Davies KP, Gibney ER, Leonard UM, Lindberg L, Woodside JV, Kiely ME, Nugent AP, Arranz E, Conway MC, McCarthy SN, O'Sullivan AM. Developing and testing personalised nutrition feedback for more sustainable healthy diets: the MyPlanetDiet randomised controlled trial protocol. Eur J Nutr. 2024 Oct;63(7):2681-2696. doi: 10.1007/s00394-024-03457-0. Epub 2024 Jul 6.
- Individual participant dataSharing planned: No. At the start of the study each participant will have a study code assigned to them. All of the data from the trials will be stored using these unique study codes. A file will be set up which will be stored in a location separate to the study data. This file will contain a list which will link each participants contact details to the corresponding ID code. All stored information will be encrypted and protected by a password that only the researcher and PI will know.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Aifric O'Sullivan, PhD principal investigator
University College Dublin
3 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Healthy climate-friendly dietary guidelines and Healthy dietary guidelines in people with Dietary Habits and Healthy Diet, run by University College Dublin at 3 sites in 2 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 4 Oct 2023. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in Ireland, United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Diet-related greenhouse gas emissions reported as kilograms of carbon dioxide equivalents per day (time frame: 12 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05253547, which also lists 4 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Oct 2023.