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ObesityDISGAPNCT04051190

Effect of Diet Versus Sleeve Gastrectomy and Gastric Bypass on Appetite

A study testing VLED group, Sleeve Gastrectomy group and Gastric Bypass group in people with Obesity, run by Norwegian University of Science and Technology at 2 sites in Norway.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

The biggest challenge in obesity management is maintaining weight loss in the long-term. Currently, bariatric surgery is the most effective treatment, leading to sustained weight loss that is not yet achievable with lifestyle intervention (e.g. diet). Read more about this study

Who is it for?
Ages 18 to 65 years
Conditions the study is for
Obesity
What is being tested?
VLED group, Sleeve Gastrectomy group and Gastric Bypass group
Type of treatment
Surgery or procedure
Could I receive a placebo?
No, everyone receives an active treatment
How many people
54 participants
Where
2 sitesNorway
Study dates
2 Sep 2019to 31 Dec 2022
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 65 years
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • scheduled for bariatric surgery
  • patient in obesity clinic
  • Body mass index (BMI) 35-55

Who cannot join

  • Currently taking medication known to affect energy metabolism or appetite
  • Current cancer diagnosis
  • Substance abuse
  • Enrolled in another obesity treatment
  • Eating disorders
  • pre-existing endocrine disorders (e.g. diabetes) will not be excluded, but final analysis will controlled for these conditions

Trial locations and contacts

2 sites in 1 country.

Norway2 sites

  • Namsos Hospital

    Namsos

  • St. Olavs Hospital

    Trondheim

Other trials in Norway

About this study

Official title: Effects of Diet-induced Weight Loss Versus Sleeve Gastrectomy and Gastric Bypass on Homeostatic and Hedonic Appetite Markers and Gut Microbiota

The biggest challenge in obesity management is maintaining weight loss in the long-term. Currently, bariatric surgery is the most effective treatment, leading to sustained weight loss that is not yet achievable with lifestyle intervention (e.g. diet). The reasons behind its success is still not clearly understood, but beneficial changes in the homeostatic and hedonic appetite systems (the two major physiological regulators of appetite), along with the microbiome (known to have a mediatory effect on appetite) have been shown to occur after bariatric surgery. These alterations are in opposition to what is seen after diet-induced weight loss. Today, the component of appetite regulation that drives bariatric surgeys' long-term success is still unknown. By comparing a lifestyle and surgical intervention in parallel, the investigators can observe the impact of a similar magnitude of weight loss on these three domains of appetite regulation simultaneously, thereby illuminating the mechanisms behind bariatric surgerys' success.

Conditions
Obesity
Being tested
VLED group, Sleeve Gastrectomy group, Gastric Bypass group
Keywords
diet, bariatric surgery, appetite
Medical subject headings
Obesity

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • VLED groupDietary supplement

    Also called very-low-energy-diet

    10-week weight loss period with total meal replacement, consisting of 750 kcal/day. Measurements will be taken at baseline (before diet start), 10 weeks after intervention start (Wk11), and at 1 year.

  • Sleeve Gastrectomy groupProcedure or surgery

    Standard clinical practice with 2-week diet consisting of 750 kcal/day prior to surgery. The pre- and post-surgical diet of this group will be matched with the VLED group in macro- and micronutrient composition. Measurements will be taken at baseline (before diet start), 10 weeks after intervention start (Wk11), and 1 year after surgery (sleeve gastrectomy)

  • Gastric Bypass groupProcedure or surgery

    Standard clinical practice with 2-week diet consisting of 750 kcal/day prior to surgery. The pre- and post-surgical diet of this group will be matched with the VLED group in macro- and micronutrient composition. Measurements will be taken at baseline (before diet start), 10 weeks after intervention start (Wk11), and 1 year after surgery (gastric bypass)

Study groups in NCT04051190
Study groupRoleWhat they receive
VLED groupExperimentalParticipants will undergo a 10-week VLED.
Receives: Dietary Supplement: VLED group
Sleeve Gastrectomy groupExperimentalParticipants will undergo standard clinical practice prior to surgery.
Receives: Dietary Supplement: VLED group; Procedure: Sleeve Gastrectomy group
Gatric Bypass groupExperimentalParticipants will undergo standard clinical practice prior to surgery.
Receives: Dietary Supplement: VLED group; Procedure: Gastric Bypass group

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Postprandial blood plasma concentration of Glucagon-like peptide-1 (GLP-1, satiety hormone)

    Blood samples will be collected at fasting, and then every 30 minutes after a standardized test meal up to 150 minutes. A radioimmunoassay method will be used to measure the concentration of total GLP-1. This method measures antigen concentrations by the use of antibodies.

    Measured: Week 11

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted9 Aug 2019
  2. Study start2 Sep 2019
  3. Primary completion31 Dec 2022
  4. Study completion31 Dec 2022

Resources

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
Treatment
Allocation
Non-randomised
Intervention model
Parallel groups
Masking
None (open label)
Enrolment
54 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT04051190
Sponsor's protocol ID
2019/252
Acronym
DISGAP
Status last verified
Jul 2023
First submitted
7 Aug 2019
Last updated
25 Jul 2023
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Publications

  • Finn A, Cedillo Y, Aukan M, Gower B, Martins C. Glucose-Dependent Insulinotropic Polypeptide and Glucagon After Weight Loss Induced by Diet or Bariatric Surgery. Obesity (Silver Spring). 2025 Dec;33(12):2277-2288. doi: 10.1002/oby.70049. Epub 2025 Sep 29.

    PubMed 41024443

  • Aukan MI, Rehfeld JF, Holst JJ, Martins C. Plasma concentration of gastrointestinal hormones and subjective appetite ratings after diet or bariatric surgery: 1-year results from the DISGAP study. Int J Obes (Lond). 2025 Feb;49(2):306-314. doi: 10.1038/s41366-024-01658-5. Epub 2024 Nov 21.

    PubMed 39572763

  • Martins C, Aukan MI, De Luca M. Lower levels of plasma syndecan-4 are associated with loss of body weight and fat-free mass after bariatric surgery. BMC Res Notes. 2024 Jun 15;17(1):164. doi: 10.1186/s13104-024-06822-8.

    PubMed 38879520

  • Martins C, Nymo S, Aukan MI, Roekenes JA, Coutinho SR, Hunter GR, Gower BA. Association between ss-Hydroxybutyrate Plasma Concentrations after Hypocaloric Ketogenic Diets and Changes in Body Composition. J Nutr. 2023 Jul;153(7):1944-1949. doi: 10.1016/j.tjnut.2023.05.010. Epub 2023 May 12.

    PubMed 37182692

  • Aukan MI, Brandsaeter IO, Skarvold S, Finlayson G, Nymo S, Coutinho S, Martins C. Changes in hedonic hunger and food reward after a similar weight loss induced by a very low-energy diet or bariatric surgery. Obesity (Silver Spring). 2022 Oct;30(10):1963-1972. doi: 10.1002/oby.23535. Epub 2022 Aug 31.

    PubMed 36046953

  • Nymo S, Lundanes J, Aukan M, Sandvik J, Johnsen G, Graeslie H, Larsson I, Martins C. Diet and physical activity are associated with suboptimal weight loss and weight regain 10-15 years after Roux-en-Y gastric bypass: A cross-sectional study. Obes Res Clin Pract. 2022 Mar-Apr;16(2):163-169. doi: 10.1016/j.orcp.2022.03.006. Epub 2022 Apr 4.

    PubMed 35393266

Questions about this trial

What is this clinical trial studying?

A study testing VLED group, Sleeve Gastrectomy group and Gastric Bypass group in people with Obesity, run by Norwegian University of Science and Technology at 2 sites in Norway.

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 3 inclusion and 6 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 25 Jul 2023. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 2 sites in Norway. 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?

Postprandial blood plasma concentration of Glucagon-like peptide-1 (GLP-1, satiety hormone) (time frame: Week 11). 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 NCT04051190, which also lists 6 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 25 Jul 2023.

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