ObesityObesiPETNCT05359887
PET-study on the Role of the Reward System in Weight Loss After Bariatric Surgery
A study testing standardized liquid mixed meal Nutridrink® in people with Obesity, run by University Medical Center Groningen at 1 site in Netherlands.
Trial summary
Bariatric surgery (BS) is currently the most effective treatment in severe obesity. However, a considerable percentage of patients undergoing BS fail to lose sufficient weight or regain weight after initial weight loss during long-term follow-up, which may be attributed to personality traits and pathological eating… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Obesity
- What is being tested?
- standardized liquid mixed meal Nutridrink®
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 30 participants
- Where
- 1 siteNetherlands
- Study dates
- 1 Dec 2022to 31 Dec 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
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 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Bariatric surgery 24-36 months prior to the study
- Adult (over 18y old)
- Mentally capable to understand the consequences of the procedure and make his or her own choice without coercion
- Able to undergo PET and MRI, according to the investigator's assessment
- Native speaking
- Able to participate in follow-up
- Written informed consent
Who cannot join
- Presence of a DSM-IV axis 1 disorder
- The use of drugs that bind to dopamine D2/3 receptors, including various classes of antipsychotics and antidepressants
- History of stroke, brain tumor, Parkinson's Disease or dementia
- History of head trauma with loss of consciousness
- Alcohol or substance abuse in the last 6 months
- Alcohol consumption 24h prior to PET scanning
Show all 13Show fewer
- Smoking or other forms of nicotine intake 12 hours prior to PET scanning
- Use of anorectic drugs in the last 6 months
- Current pregnancy
- Medication for Diabetes Mellitus
- Claustrophobia
- The presence of implanted metal objects of the type which may concentrate radiofrequency fields or cause tissue damage from twisting in a magnetic field (such as certain implanted devices, shrapnel, ocular metal shavings)
- Patients with a bodyweight > 200kg will be excluded to ensure the maximum load of the camera bed of the PET-scanner (227 kg) is not exceeded.
Trial locations and contacts
1 site in 1 country.
About this study
Bariatric surgery (BS) is currently the most effective treatment in severe obesity. However, a considerable percentage of patients undergoing BS fail to lose sufficient weight or regain weight after initial weight loss during long-term follow-up, which may be attributed to personality traits and pathological eating behaviour. Previous positron emission tomography (PET) studies have shown reduced dopamine D2 receptor availability in obese patients and upregulation of this availability following successful BS in the brain's reward system. Dopamine D2 receptor availability in patients with unsuccessful BS has not been investigated to date.
- Conditions
- Obesity
- Being tested
- standardized liquid mixed meal Nutridrink®
- Keywords
- Obesity, Reward system, PET-scan, [11C]-Raclopride
- Medical subject headings
- Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
standardized liquid mixed meal Nutridrink®Other
Administration of food in controlled situation
| Study group | Role | What they receive |
|---|---|---|
| Unsuccessful BS (Total Weight Loss (TWL) < 20%) | Experimental | Fifteen who had unsuccessful BS (Total Weight Loss (TWL) < 20%) Receives: Other: standardized liquid mixed meal Nutridrink® |
| Successful BS (TWL > 25%). | Experimental | Fifteen who had successful BS (TWL > 25%). Receives: Other: standardized liquid mixed meal Nutridrink® |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in [11C]-raclopride binding potential in the brain's reward system between study groups before and after a food challenge.
Pre- and post-eating changes in dopamine D2 receptor availability as indexed by the [11C]-raclopride binding potential in the brain's reward system between subjects who underwent successful vs unsuccessful bariatric surgery
Measured: -50 minutes (before start of PET scanning), 0 minutes (during PET break, before mixed meal), 30 minutes (after second phase of PET-scanning)
Secondary outcomes (2)
The correlation between [11C]-raclopride binding potential in the brain's reward system and of questionnaires and diaries
The correlation between questionnaires on eating habits (EDE-Q, REO, YFAS) and quality of life (OBESI-Q) in patients who had successful vs unsuccessful BS and [11C]-raclopride binding potential.
Measured: Pre-intervention
The correlation between [11C]-raclopride binding potential in the brain's reward system and of gut hormones.
The relation between fasting or fed (gut) hormone concentrations and dopamine D2 receptor availability in the reward system.
Measured: -50 minutes (before start of PET scanning), 0 minutes (during PET break, before mixed meal), 30 minutes (after second phase of PET-scanning), 60 - 90 - 120 minutes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 May 2022
- Study start1 Dec 2022
- Primary completion31 Dec 2026 (estimated)
- Study completion31 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for ObesityStudies of the same condition, open and under way.
- More trials run by University Medical Center GroningenThe sponsor's other registered studies.
- 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
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Medical Center Groningen
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05359887
- Sponsor's protocol ID
- UMCG202100632
- Acronym
- ObesiPET
- Status last verified
- Apr 2026
- First submitted
- 12 Apr 2022
- Last updated
- 29 Apr 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 29 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- PET-study on the Role of the Reward System in Weight Loss After Bariatric Surgery
- ClinicalTrials.gov ID
- NCT05359887
- Acronym / sponsor ID
- ObesiPET / UMCG202100632
- Conditions
- Obesity
- Keywords
- Obesity, Reward system, PET-scan, [11C]-Raclopride
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- University Medical Center GroningenUniversity, hospital or other
- Study start
- 1 Dec 2022 (actual)
- Primary completion
- 31 Dec 2026 (estimated)
- Study completion
- 31 Dec 2026 (estimated)
- First posted
- 4 May 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.
Bariatric surgery (BS) is currently the most effective treatment in severe obesity. However, a considerable percentage of patients undergoing BS fail to lose sufficient weight or regain weight after initial weight loss during long-term follow-up, which may be attributed to personality traits and pathological eating behaviour. Previous positron emission tomography (PET) studies have shown reduced dopamine D2 receptor availability in obese patients and upregulation of this availability following successful BS in the brain's reward system. Dopamine D2 receptor availability in patients with unsuccessful BS has not been investigated to date.
Study design
- Primary purpose
- Other
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Unsuccessful BS (Total Weight Loss (TWL) < 20%) | Experimental | Other: standardized liquid mixed meal Nutridrink®Fifteen who had unsuccessful BS (Total Weight Loss (TWL) < 20%) |
| Successful BS (TWL > 25%). | Experimental | Other: standardized liquid mixed meal Nutridrink®Fifteen who had successful BS (TWL > 25%). |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- Bariatric surgery 24-36 months prior to the study
- Adult (over 18y old)
- Mentally capable to understand the consequences of the procedure and make his or her own choice without coercion
- Able to undergo PET and MRI, according to the investigator's assessment
- Native speaking
Key exclusion criteria (13 listed)
- Presence of a DSM-IV axis 1 disorder
- The use of drugs that bind to dopamine D2/3 receptors, including various classes of antipsychotics and antidepressants
- History of stroke, brain tumor, Parkinson's Disease or dementia
- History of head trauma with loss of consciousness
- Alcohol or substance abuse in the last 6 months
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 |
|---|---|---|
| standardized liquid mixed meal Nutridrink®Administration of food in controlled situation | Other | Successful BS (TWL > 25%)., Unsuccessful BS (Total Weight Loss (TWL) < 20%) |
Primary outcome
Change in [11C]-raclopride binding potential in the brain's reward system between study groups before and after a food challenge.
Time frame: -50 minutes (before start of PET scanning), 0 minutes (during PET break, before mixed meal), 30 minutes (after second phase of PET-scanning)
Pre- and post-eating changes in dopamine D2 receptor availability as indexed by the [11C]-raclopride binding potential in the brain's reward system between subjects who underwent successful vs unsuccessful bariatric surgery
2 secondary outcomes
The correlation between [11C]-raclopride binding potential in the brain's reward system and of questionnaires and diaries
Time frame: Pre-intervention
The correlation between [11C]-raclopride binding potential in the brain's reward system and of gut hormones.
Time frame: -50 minutes (before start of PET scanning), 0 minutes (during PET break, before mixed meal), 30 minutes (after second phase of PET-scanning), 60 - 90 - 120 minutes
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Apr 2026.
- Individual participant dataSharing planned: No
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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.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing standardized liquid mixed meal Nutridrink® in people with Obesity, run by University Medical Center Groningen at 1 site in Netherlands.
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 7 inclusion and 13 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: under way, not looking for participants, as of the sponsor's last update on 29 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Netherlands. 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?
This study is still under way. Results are not available in the source record yet.
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?
Change in [11C]-raclopride binding potential in the brain's reward system between study groups before and after a food challenge. (time frame: -50 minutes (before start of PET scanning), 0 minutes (during PET break, before mixed meal), 30 minutes (after second phase of PET-scanning)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 29 Apr 2026.