Diet, HealthyNUTRACOBNCT04942093
NUTritional Impact of a Hypocaloric Hyperprotein Diet Before Obesity Surgery
A study testing With low-calorie, high-protein diet and Without low-calorie, high-protein diet in people with Diet, Healthy and Obesity, Visceral, run by University Hospital, Rouen at 3 sites in France.
Trial summary
Obesity is a major public health problem and is constantly on the rise. Therapeutic approaches based on dietary advice, physical activity and the management of psychological difficulties are not always sufficient to achieve a lasting weight reduction. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Diet, Healthy, Obesity, Visceral, Bariatric Surgery Candidate
- What is being tested?
- With low-calorie, high-protein diet and Without low-calorie, high-protein diet
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 200 participants
- Where
- 3 sitesFrance
- Study dates
- 9 Oct 2023to 20 Mar 2027
- 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 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patient eligible for bariatric surgery (according to HAS criteria) whose sleeve gastrectomy is scheduled
- Patient with morbid obesity (BMI ≥ 40)
- Age ≥ 18 years and ≤ 65 years
- Haemoglobinemia ≥ 12 g/dL in men and ≥ 11 g/dL in women
- Patient speaking and understanding French
- Adult having read and understood the information letter and signed the consent form
Show all 9Show fewer
- Woman of childbearing age with effective / very effective contraception (Cf. CTFG) (estrogen-progestin or intrauterine device or tubal ligation) prior to surgery and a negative -HCG blood pregnancy test at inclusion, for the duration of the study
- Postmenopausal woman: confirmatory diagnosis (non-medically induced amenorrhoea for at least 12 months prior to the inclusion visit)
- Patient affiliated with, or beneficiary of a social security (health insurance) category
Who cannot join
- Contraindication to bariatric surgery detected during the preoperative assessment
- Medical contraindication to a restrictive diet
- Type I or II insulin-requiring diabetes
- Severe renal insufficiency defined by a blood filtration rate < 30 mL/min
- Person wearing a pacemaker or any other implant with the same functions (cochlear implant, bladder battery, etc.)
- Person deprived of liberty by an administrative or judicial decision or person placed under judicial protection / sub-guardianship or curatorship
- A history of illness or psychological or sensory abnormality likely to prevent the subject from fully understanding the conditions required for participation in the protocol or to prevent him/her from giving informed consent
Trial locations and contacts
3 sites in 1 country. Contact the study team or a site near you to ask about taking part.
France3 sites, 3 recruiting
- Recruiting
Ch Dieppe
Dieppe
Annabelle FERON, aferon@ch-dieppe.fr
- Recruiting
HPE
Le Havre
Emeline RIGAUDIERE, E.rigaudiere@ramsaygds.fr
- Recruiting
CHU de ROUEN
Rouen, 76 000
Christèle DAVID, christele.david@chu-rouen.fr
About this study
Obesity is a major public health problem and is constantly on the rise. Therapeutic approaches based on dietary advice, physical activity and the management of psychological difficulties are not always sufficient to achieve a lasting weight reduction.
Bariatric surgery (or obesity surgery), accompanied by therapeutic education and adequate medical and dietary monitoring, can lead to significant and lasting weight loss. It is indicated as a second-line treatment for patients who have failed medical treatment, whose BMI is greater than or equal to 40 or whose BMI is greater than or equal to 35 with comorbidities (type 2 diabetes, arterial hypertension, obstructive sleep apnoea-hypopnoea syndrome, severe joint disorders).
Read more
The surgeon may be very bothered by the intra-abdominal fat mass and especially by steatotic hepatomegaly (increase in the size of the liver and its fat load).
Faced with this problem, various preoperative strategies such as the placement of an intra gastric balloon have been tried to decrease the size of the liver but a systematic review from 2016 indicates that a low calorie diet is preferable. Preoperative weight loss can reduce fat load and liver volume very rapidly. This meta-analysis shows that all low-calorie, high-protein diets are effective and that the optimal duration (4 weeks), compliance and tolerance are important factors for success.
Read the detailed description
Obesity is a major public health problem and is constantly on the rise. Therapeutic approaches based on dietary advice, physical activity and the management of psychological difficulties are not always sufficient to achieve a lasting weight reduction.
Bariatric surgery (or obesity surgery), accompanied by therapeutic education and adequate medical and dietary monitoring, can lead to significant and lasting weight loss. It is indicated as a second-line treatment for patients who have failed medical treatment, whose BMI is greater than or equal to 40 or whose BMI is greater than or equal to 35 with comorbidities (type 2 diabetes, arterial hypertension, obstructive sleep apnoea-hypopnoea syndrome, severe joint disorders).
The surgeon may be very bothered by the intra-abdominal fat mass and especially by steatotic hepatomegaly (increase in the size of the liver and its fat load).
Faced with this problem, various preoperative strategies such as the placement of an intra gastric balloon have been tried to decrease the size of the liver but a systematic review from 2016 indicates that a low calorie diet is preferable. Preoperative weight loss can reduce fat load and liver volume very rapidly. This meta-analysis shows that all low-calorie, high-protein diets are effective and that the optimal duration (4 weeks), compliance and tolerance are important factors for success.
However, there is no consensus on the benefit/risk balance of a preoperative diet and there is considerable variability in approach at national and international level.
The present clinical study involves a triad of dietician, surgeon, physician (endocrinologist/nutritionist or internist) to secure this diet. It could provide a database to help estimate the risk of undernutrition in the obese subject.
This diet, designed to facilitate the surgical procedure and potentially reduce intraoperative complications, is inexpensive, easily accessible and reproducible by other teams. This innovative management could standardise the preoperative management of patients undergoing bariatric surgery at national level. It would also improve the results of bariatric surgery both in the short term by reducing complications and in the long term by increasing weight reduction as reported in the Livhits meta-analysis. The risk of undernutrition should be reduced by this hypocaloric hyperprotein diet and consequently cancel out the increased risk of mortality, infections, delayed healing, longer hospital stay and the costs that this would entail.
- Being tested
- With low-calorie, high-protein diet, Without low-calorie, high-protein diet
- Keywords
- diet, obesity, bariatric surgery
- Medical subject headings
- Obesity, Abdominal, Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
With low-calorie, high-protein dietDietary supplement
A low-calorie, high-protein diet will be prescribed to the patient for a period of 4 weeks. The diet will be done the 4 weeks before the bariatric surgery
Without low-calorie, high-protein dietDietary supplement
A low-calorie, high-protein diet will not be prescribed to the patient for a period of 4 weeks.
| Study group | Role | What they receive |
|---|---|---|
| With diet | Experimental | A low-calorie, high-protein diet will be prescribed to the patient for a period of 4 weeks. The diet will be done the 4 weeks before the bariatric surgery Receives: Dietary Supplement: With low-calorie, high-protein diet |
| Without diet | Other | A low-calorie, high-protein diet will not be prescribed to the patient for a period of 4 weeks. Receives: Dietary Supplement: Without low-calorie, high-protein diet |
What is being measured
The primary outcome is the main question the study is designed to answer.
Poor diet tolerance
At least one of the following biological abnormalities at the end of the diet period:
- Lymphopenia acquired during the diet
- Anemia (Hb<11g/dL for men Hb<10g/dL for women) or a decrease in hemoglobin of more than 2 g/dL
- Onset or worsening of vitamin B1 deficiency from baseline (Vit B1 < 78 nmol/L)
OR
At least one of the following clinical abnormalities:
- Decrease in muscle strength (difference in muscle strength measured with a HandGrip at Visit 2 and Visit 3) greater than three standard deviations from the matched Visit 3 - visit 2 differences of the control group after removal of measurement bias on a log-transformed strength variable, associated with weight loss > 5% in 1 month or a decrease in percent lean mass ≥ 1% relative to visit 2
- Any permanent discontinuation
Measured: 4 weeks after the beggining of the diet
Secondary outcomes (10)
Weight loss
Weight difference between Visit 3 and Visit 2
Measured: 4 weeks after the beggining of the diet and 3 months postoperatively
Reduced muscle strength
Difference in muscle strength measured with a HandGrip at Visit 2 and Visit 3)
Measured: 4 weeks after the beggining of the diet
Comparison of the quality of life between "with diet" and "without diet" with "EQVOD" questionnaire
Evaluated using the EQVOD questionnaire at baseline (V2), end of diet (V3) and 3 months postoperatively Score from 36 to 180
Measured: Baseline, 4 weeks after the beggining of the diet and 3 months postoperatively
Evolution of physical activity
Physical activity evaluated using the Ricci et Gagnon questionnaire at baseline (V2), end of diet (V3) and 3 months postoperatively
Measured: Baseline, 4 weeks after the beggining of the diet and 3 months postoperatively
Digestive tolerance
Digestive tolerance evaluated using auto-questionnaire about nausea, vomiting, diarrhoea, constipation forthe interventional group, in the month of the diet
Measured: during the 4 weeks of the diet
Compliance
Evaluated by a food diary and the full bottles (not consumed) brought back for the intervention group, in the month of the diet
Measured: during the 4 weeks of the diet
Degree of exposure
Assessment of the degree of exposure of the oesogastric junction and hepatomegaly on a subjective scale of 1 to 5 by the surgeon
Measured: one day from surgery
Operating time
Number of hours and minuts about surgery
Measured: one day from surgery
Length of hospital stay
Number of days in hospital for the surgery
Measured: Four months from surgery
Intraoperative and postoperative complications
Delayed healing, infection and cancellation of surgery or conversion to laparotomy) up to 3 months post-operatively
Measured: Between surgery and 3 months postoperatively
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Jun 2021
- Study start9 Oct 2023
- Primary completion20 Nov 2026 (estimated)
- Study completion20 Mar 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Diet, HealthyStudies of the same condition, open and under way.
- More trials run by University Hospital, RouenThe 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
- Supportive care
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 200 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Hospital, Rouen
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04942093
- Sponsor's protocol ID
- 2019/0414/HP
- Acronym
- NUTRACOB
- Status last verified
- Sep 2025
- First submitted
- 11 Jun 2021
- Last updated
- 22 Sep 2025
- 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 22 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- NUTritional Impact of a Hypocaloric Hyperprotein Diet Before Obesity Surgery
- ClinicalTrials.gov ID
- NCT04942093
- Acronym / sponsor ID
- NUTRACOB / 2019/0414/HP
- Keywords
- diet, obesity, bariatric surgery
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 200 participants (estimated)
- Lead sponsor
- University Hospital, RouenUniversity, hospital or other
- Study start
- 9 Oct 2023 (actual)
- Primary completion
- 20 Nov 2026 (estimated)
- Study completion
- 20 Mar 2027 (estimated)
- First posted
- 28 Jun 2021 (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.
Obesity is a major public health problem and is constantly on the rise. Therapeutic approaches based on dietary advice, physical activity and the management of psychological difficulties are not always sufficient to achieve a lasting weight reduction.
Bariatric surgery (or obesity surgery), accompanied by therapeutic education and adequate medical and dietary monitoring, can lead to significant and lasting weight loss. It is indicated as a second-line treatment for patients who have failed medical treatment, whose BMI is greater than or equal to 40 or whose BMI is greater than or equal to 35 with comorbidities (type 2 diabetes, arterial hypertension, obstructive sleep apnoea-hypopnoea syndrome, severe joint disorders).
The surgeon may be very bothered by the intra-abdominal fat mass and especially by steatotic hepatomegaly (increase in the size of the liver and its fat load).
Faced with this problem, various preoperative strategies such as the placement of an intra gastric balloon have been tried to decrease the size of the liver but a systematic review from 2016 indicates that a low calorie diet is preferable. Preoperative weight loss can reduce fat load and liver volume very rapidly. This meta-analysis shows that all low-calorie, high-protein diets are effective and that the optimal duration (4 weeks), compliance and tolerance are important factors for success.
Detailed description
Obesity is a major public health problem and is constantly on the rise. Therapeutic approaches based on dietary advice, physical activity and the management of psychological difficulties are not always sufficient to achieve a lasting weight reduction.
Bariatric surgery (or obesity surgery), accompanied by therapeutic education and adequate medical and dietary monitoring, can lead to significant and lasting weight loss. It is indicated as a second-line treatment for patients who have failed medical treatment, whose BMI is greater than or equal to 40 or whose BMI is greater than or equal to 35 with comorbidities (type 2 diabetes, arterial hypertension, obstructive sleep apnoea-hypopnoea syndrome, severe joint disorders).
The surgeon may be very bothered by the intra-abdominal fat mass and especially by steatotic hepatomegaly (increase in the size of the liver and its fat load).
Faced with this problem, various preoperative strategies such as the placement of an intra gastric balloon have been tried to decrease the size of the liver but a systematic review from 2016 indicates that a low calorie diet is preferable. Preoperative weight loss can reduce fat load and liver volume very rapidly. This meta-analysis shows that all low-calorie, high-protein diets are effective and that the optimal duration (4 weeks), compliance and tolerance are important factors for success.
However, there is no consensus on the benefit/risk balance of a preoperative diet and there is considerable variability in approach at national and international level.
The present clinical study involves a triad of dietician, surgeon, physician (endocrinologist/nutritionist or internist) to secure this diet. It could provide a database to help estimate the risk of undernutrition in the obese subject.
This diet, designed to facilitate the surgical procedure and potentially reduce intraoperative complications, is inexpensive, easily accessible and reproducible by other teams. This innovative management could standardise the preoperative management of patients undergoing bariatric surgery at national level. It would also improve the results of bariatric surgery both in the short term by reducing complications and in the long term by increasing weight reduction as reported in the Livhits meta-analysis. The risk of undernutrition should be reduced by this hypocaloric hyperprotein diet and consequently cancel out the increased risk of mortality, infections, delayed healing, longer hospital stay and the costs that this would entail.
Study design
- Primary purpose
- Supportive care
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| With diet | Experimental | Dietary Supplement: With low-calorie, high-protein dietA low-calorie, high-protein diet will be prescribed to the patient for a period of 4 weeks. The diet will be done the 4 weeks before the bariatric surgery |
| Without diet | Other | Dietary Supplement: Without low-calorie, high-protein dietA low-calorie, high-protein diet will not be prescribed to the patient for a period of 4 weeks. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (9 listed)
- Patient eligible for bariatric surgery (according to HAS criteria) whose sleeve gastrectomy is scheduled
- Patient with morbid obesity (BMI ≥ 40)
- Age ≥ 18 years and ≤ 65 years
- Haemoglobinemia ≥ 12 g/dL in men and ≥ 11 g/dL in women
- Patient speaking and understanding French
Key exclusion criteria (7 listed)
- Contraindication to bariatric surgery detected during the preoperative assessment
- Medical contraindication to a restrictive diet
- Type I or II insulin-requiring diabetes
- Severe renal insufficiency defined by a blood filtration rate < 30 mL/min
- Person wearing a pacemaker or any other implant with the same functions (cochlear implant, bladder battery, etc.)
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 |
|---|---|---|
| With low-calorie, high-protein dietA low-calorie, high-protein diet will be prescribed to the patient for a period of 4 weeks. The diet will be done the 4 weeks before the bariatric surgery | Dietary supplement | With diet |
| Without low-calorie, high-protein dietA low-calorie, high-protein diet will not be prescribed to the patient for a period of 4 weeks. | Dietary supplement | Without diet |
Primary outcome
Poor diet tolerance
Time frame: 4 weeks after the beggining of the diet
At least one of the following biological abnormalities at the end of the diet period: * Lymphopenia acquired during the diet * Anemia (Hb<11g/dL for men Hb<10g/dL for women) or a decrease in hemoglobin of more than 2 g/dL * Onset or worsening of vitamin B1 deficiency from baseline (Vit B1 < 78 nmol/L) OR At least one of the following clinical abnormalities: * Decrease in muscle strength (difference in muscle strength measured with a HandGrip at Visit 2 and Visit 3) greater than three standard deviations from the matched Visit 3 - visit 2 differences of the control group after removal of measurement bias on a log-transformed strength variable, associated with weight loss > 5% in 1 month or a decrease in percent lean mass ≥ 1% relative to visit 2 * Any permanent discontinuation
10 secondary outcomes
Weight loss
Time frame: 4 weeks after the beggining of the diet and 3 months postoperatively
Reduced muscle strength
Time frame: 4 weeks after the beggining of the diet
Comparison of the quality of life between "with diet" and "without diet" with "EQVOD" questionnaire
Time frame: Baseline, 4 weeks after the beggining of the diet and 3 months postoperatively
Evolution of physical activity
Time frame: Baseline, 4 weeks after the beggining of the diet and 3 months postoperatively
Digestive tolerance
Time frame: during the 4 weeks of the diet
Compliance
Time frame: during the 4 weeks of the diet
Degree of exposure
Time frame: one day from surgery
Operating time
Time frame: one day from surgery
Length of hospital stay
Time frame: Four months from surgery
Intraoperative and postoperative complications
Time frame: Between surgery and 3 months postoperatively
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 22 Sep 2025.
- Individual participant dataSharing planned: No
Related trials for Diet, Healthy
Not yet recruiting
Testing a Smartphone App to Support a Mediterranean Diet and Strength Exercise
Treatment Adherence and Compliance, Resistance Exercise
Not yet recruiting
Effects of Ad Libitum Ultra-Processed Diet on Brain Dopamine in Humans
Healthy Volunteers
Recruiting
Nutrition Outcomes Using a Randomized Intervention Via Smartphone on Dietary Habits
Healthy Adult Participants, Mindful Eating Intervention
Not yet recruiting
Web-Based Sustainable Food Literacy Program for University Students
Food Literacy, Healthy Eating
Recruiting
Environmental Harm Menu Labels and Overall Dietary Quality
Food Choices
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.
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing With low-calorie, high-protein diet and Without low-calorie, high-protein diet in people with Diet, Healthy and Obesity, Visceral, run by University Hospital, Rouen at 3 sites in France.
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 9 inclusion and 7 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: looking for participants now, as of the sponsor's last update on 22 Sep 2025. 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 France. 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?
Contact Christèle DAVID (+33232888624, christele.david@chu-rouen.fr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Poor diet tolerance (time frame: 4 weeks after the beggining of the diet). 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 22 Sep 2025.