NUTritional Impact of a Hypocaloric Hyperprotein Diet Before Obesity Surgery (NUTRACOB)

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.

Study Overview

• Status: Recruiting
• Conditions: Bariatric Surgery Candidate; Diet, Healthy; Obesity, Visceral
• Intervention / Treatment: Dietary supplement: With low-calorie, high-protein diet; Dietary supplement: Without low-calorie, high-protein diet

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 Type: Interventional
• Enrollment (Estimated): 200
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Christèle DAVID; Phone Number: +33232888624; Email: christele.david@chu-rouen.fr
• Study Contact Backup: Name: Déborah LEBEDIEFF; Phone Number: +33232888265; Email: deborah.lebedieff@chu-rouen.fr

Study Locations

• France
  • Dieppe, France
    • Recruiting
    • Ch Dieppe
    • Contact: Annabelle FERON; Email: aferon@ch-dieppe.fr
  • Le Havre, France
    • Recruiting
    • HPE
    • Contact: Emeline RIGAUDIERE; Email: E.rigaudiere@ramsaygds.fr
  • Rouen, France, 76 000
    • Recruiting
    • CHU de Rouen
    • Contact: Christèle DAVID; Email: christele.david@chu-rouen.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• 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
• 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

Exclusion Criteria:

• 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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: With diet; 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	Dietary supplement: With low-calorie, high-protein diet; 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
Other: Without diet; A low-calorie, high-protein diet will not be prescribed to the patient for a period of 4 weeks.	Dietary supplement: Without low-calorie, high-protein diet; A low-calorie, high-protein diet will not be prescribed to the patient for a period of 4 weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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	4 weeks after the beggining of the diet

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Weight loss	Weight difference between Visit 3 and Visit 2	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)	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	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	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	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	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	one day from surgery
Operating time	Number of hours and minuts about surgery	one day from surgery
Length of hospital stay	Number of days in hospital for the surgery	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	Between surgery and 3 months postoperatively

Collaborators and Investigators

• Sponsor: University Hospital, Rouen

Study record dates

Study Major Dates

• Study Start (Actual): October 9, 2023
• Primary Completion (Estimated): November 20, 2026
• Study Completion (Estimated): March 20, 2027

Study Registration Dates

• First Submitted: June 11, 2021
• First Submitted That Met QC Criteria: June 18, 2021
• First Posted (Actual): June 28, 2021

Study Record Updates

• Last Update Posted (Actual): September 22, 2025
• Last Update Submitted That Met QC Criteria: September 16, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: obesity; bariatric surgery; diet
• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Overweight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Obesity; Obesity, Abdominal; Therapeutics; Diet, Food, and Nutrition; Physiological Phenomena; Nutritional Physiological Phenomena; Diet Therapy; Nutrition Therapy; Diet; Diet, High-Protein
• Other Study ID Numbers: 2019/0414/HP

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No