Impact of a Pro-diversity Gut Microbiota Diet After a Bariatric Surgery on Gut Microbiota, Eating Behaviour and Sensory Function

N/ANot Yet RecruitingNCT07268508

Hospices Civils de Lyon60 enrolled

Overview

Bariatric surgery is the most effective treatment for long-term weight loss and reducing obesity-related health risks. It alters the gastrointestinal tract as well as metabolic and hormonal functions, influencing eating behaviour. However, weight loss outcomes and long-term maintenance vary between patients, likely due to changes in the gut microbiota. Dietary recommendations aimed at improving microbiota diversity could help support sustained weight loss after surgery. The BariaGut Taste study aims to compare two dietary approaches following bariatric surgery: nutritional counselling promoting gut microbiota diversity versus standard nutritional counselling. One year after surgery, the study will evaluate differences in microbiota diversity, changes in food preferences and eating behaviours, sensory profiles (taste, smell), levels of digestive and gut hormones fasting, before and after eating, cardiometabolic parameters, mental health, physical activity, and more, to better understand Bariatric surgery is the most effective treatment for long-term weight loss and reducing obesity-related health risks. It alters the gastrointestinal tract as well as metabolic and hormonal functions, influencing eating behaviour. However, weight loss outcomes and long-term maintenance vary between patients, likely due to changes in the gut microbiota. Dietary recommendations aimed at improving microbiota diversity could help support sustained weight loss after surgery. The BariaGut Taste study aims to compare two dietary approaches following bariatric surgery: nutritional counselling promoting gut microbiota diversity versus standard nutritional counselling. One year after surgery, the study will evaluate differences in microbiota diversity, changes in food preferences and eating behaviours, sensory profiles (taste, smell), levels of digestive and gut hormones fasting, before and after eating, cardiometabolic parameters, mental health, physical activity, and more, to better understand the mechanisms that may explain variations in response to bariatric surgery. The BariaGut Taste study is a prospective, randomized, controlled trial with two parallel groups, involving non-diabetic patients aged 25 to 65 y undergoing either sleeve gastrectomy or Roux-en-Y gastric bypass. The trial will be conducted at the digestive surgery department of Edouard Herriot Hospital, the endocrinology-diabetes-nutrition department of Lyon Sud Hospital Center, and the Human Nutrition Research Center Rhône-Alpes. 60 participants are expected to be recruited, with 30 in each arm. Participants will be enrolled before surgery during a routine care visit with the surgeon. They will then undergo a metabolic assessment visit conducted exclusively for research purposes. This visit will allow to collect baseline data on primary outcomes via blood, expired air, and stool samples, anthropometric measurements, indirect calorimetry, a battery of questionnaires (TFEQ-21, DEBQ, PHQ-9, SF36, GSES, PANAS, ESUL, BES, DERS, GAD-7, IPAQ, BAQ, GSRS, sensory alterations, Bristol and Likert scales, and FNS), computerized food preference tests (LFPQ), and a standardized, video-recorded ad libitum buffet. Participants will be followed up at 3, 6, and 12 months after surgery through visits combining clinical care and research assessments. The dietary interventions specific to each group will be provided since the 3-month visit. The assessments conducted before surgery will be repeated at 6 and 12 months, also integrating clinical care objectives. Additional blood, stool, and adipose tissue samples collected during surgery will be stored to create a biobank.

Eligibility

Sex: ALLMin age: 25 YearsMax age: 65 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Between 25 and 65 years old * Undergoing either sleeve gastrectomy or Roux-en-Y gastric bypass * With grade 3 obesity (BMI≥40 kg/m²) or with BMI≥35 kg/m² and at least one comorbidity likely to be improved after surgery, with the exception of type 2 diabetes * Signed consent form * Living less than an hour and 30 minutes from the hospital * Presence of effective and stable contraception for women of childbearing potential Exclusion Criteria: * Type 2 diabetes * Presence of a contraindication to bariatric surgery * Presence of gastrointestinal pathologies with an inflammatory component, known gastroparesis, total gastrectomy, colectomy, exocrine pancreatic insufficiency, known endocrine pathologies inducing hyperglycaemia (uncontrolled dysthyroidism, acromegaly, hypercorticism, etc.), severe chronic renal insufficiency (\< 30mL/min), or hepatocellular insufficiency * Claustrophobic * Pregnant or breastfeeding women * Taking an obesity treatment 3 months before surgery * Taking a corticoids, immunosuppression, anabolizing, or growing hormones, antibody treatments less than 3 months before inclusion * Daily taking of laxatives or drugs that can strongly interfere with the composition of the intestinal microbiota. If taken sporadically, the patient can be included at a distance (3 weeks) from the laxatives taken. * Specific diets (vegetarian, vegan or without gluten) * No French speaker * Already included in other study * Donated blood in the last two months * Without freezer access * With allergy or intolerance to food propose in ad libitum buffet

Outcomes

Primary Outcomes

Microbiota diversity 12 months after surgery

The change in the diversity of the microbiota (shot gun metagenomic analysis, counting the number of microbial genes), between before surgery and one year after surgery (delta) between the two dietary intervention groups.

Time frame: Primary outcome will be assessed three times : before the surgery, 6 and 12 months after

Secondary Outcomes

Eating behaviour during a standardised, filmed and validated ad libitum buffet : Food intake

energy intake, macro- and micronutrient intake The items chosen during the buffet from the 17 items that will be offered will be noted. The quantities in g and calories consumed of each item will be estimated from the weighing of the plates before and after the buffet, the contribution of each of the items to the energy intake will also be evaluated.

Time frame: Before the surgery and at 6 and 12 month after

Eating behaviour during a standardised, filmed and validated ad libitum buffet: Nutritional quality

Nutritional quality through analysis of the foods chosen and consumed Buffet items are classified (pre-defined classification) into seven groups based on their macronutrient content and energy density: starchy foods, meat and fish, fruits and vegetables, dairy products, sweet desserts, sauces, and sweetened beverages. They are also classified according to their fat, sugar, and protein content, and their energy density (4 groups). The quantities consumed in grams and as a percentage of energy intake per group will be assessed for each subject and per visit.

Time frame: Before the surgery and at 6 and 12 month after

Eating behaviour during a standardised, filmed and validated ad libitum buffet: Meal microstructure

time spent selecting food at the buffet, duration of ingestion, ingestion speed, total meal duration, number of bites per minute, total number of bites and bites by food type, and food choices Several indicators will be assessed for the buffet's microstructure based on the analysis of videos taken during the buffet: \- Buffet time

Time frame: Before the surgery and at 6 and 12 month after

Eating behaviour during a standardised, filmed and validated ad libitum buffet: Meal appreciation

time spent selecting food at the buffet, duration of ingestion, ingestion speed, total meal duration, number of bites per minute, total number of bites and bites by food type, and food choices Assessed with visual analog scale from 1(worse outcome) to 10 (better outcome)

Time frame: Before the surgery and at 6 and 12 month after

Eating behaviour and preferences : Behaviors

binge eating using sub-scores from tthe BES (Binge Eating Scale) for binge eating BES : Binge Eating Scale - score from 0 to 46, score of 46 = highest level of binge eating disorder

Time frame: Before the surgery and at 6 and 12 month after

Eating behaviour and preferences : Food preferences

Food preferences using the short version of the LFPQ (Leeds Food Preference Questionnaire) LFPQ : Leeds Food and Preference Questionnaire- score from 0 to 100 on preference or motivation for a type of food, high score = strong preference or motivation

Time frame: Before the surgery and at 6 and 12 month after

Appetite : hunger level

Assessed using visual analog scales rated from 0 (worse outcome) to 10 (better outcome) on the following dimensions : hunger

Time frame: Before the surgery and at 6 and 12 month after

Appetite : satiety

Assessed using visual analog scales rated rom 0 (worse outcome) to 10 (better outcome) on the following dimensions : feeling of satiety

Time frame: Before the surgery and at 6 and 12 month after

Appetite : desire to eat

Assessed using visual analog scales rated from 0 (worse outcome) to 10 (better outcome) on the following dimensions : desire to eat

Time frame: Before the surgery and at 6 and 12 month after

Appetite : prospective consumption

Assessed using visual analog scales rated from 0 (worse outcome) to 10 (better outcome) on the following dimensions : consommation

Time frame: Before the surgery and at 6 and 12 month after

Appetite : meal appreciation

Assessed using visual analog scales rated rom 0 (worse outcome) to 10 (better outcome) on the following dimensions : meal appreciation

Time frame: Before the surgery and at 6 and 12 month after

Sensory functions : detection scores

Assessed using Taste Strips tests

Time frame: Before the surgery and at 6 and 12 month after

Sensory functions : intensity

Assessed using Taste Strips tests

Time frame: Before the surgery and at 6 and 12 month after

Sensory functions : pleasantness

Assessed using Taste Strips tests

Time frame: Before the surgery and at 6 and 12 month after

Sensory functions : edibility of tastes

Assessed using Taste Strips tests

Time frame: Before the surgery and at 6 and 12 month after

Sensory functions : edibility of odors

Assessed using Taste Strips tests

Time frame: Before the surgery and at 6 and 12 month after

Self-reported alterations in sensory functions

Assessed using dedicated questions

Time frame: Before the surgery and at 6 and 12 month after

Body perception

Assessed using the BAQ questionnaire (Body Awareness Questionnaire) BAQ : Body Awarness Questionnaire - score from 13 to 65, score of 65 = positive assessment of one's body

Time frame: Before the surgery and at 6 and 12 month after

Appetite : desire to eat

Assessed using visual analog scales rated from 0 to 10 on the following dimensions: desire to eat

Time frame: Before the surgery and at 6 and 12 month after

Appetite : prospective consumption

Assessed using visual analog scales rated from 0 to 10 on the following dimensions

Time frame: Before the surgery and at 6 and 12 month after

Microbiota composition

Evaluated via gene function analysis from metagenomics data, metabolomics and short-chain fatty acid quantification

Time frame: Before the surgery and at 6 and 12 month after

Microbiota function

Evaluated via gene function analysis from metagenomics data, metabolomics and short-chain fatty acid quantification

Time frame: Before the surgery and at 6 and 12 month after

Endocrine, digestive or intestinal hormones

Blood sample to measure : Adiponectin µg/ml

Time frame: Before the surgery and at 6 and 12 month after Fasting (all except acylated ghrelin), before the buffet and 1 hour after (adiponectin, total GLP1, ghrelin, acylated ghrelin, total PYY, glucagon, GIP and FGF-19)

Exhaled gas profiles

Assessed by volatolomic signatures

Time frame: Before the surgery and at 6 and 12 month after

Cardio-metabolic profile parameters

BMI will be assessed

Time frame: Before the surgery and at 6 and 12 month after

Cardio-metabolic profile parameters

Energy metabolism by indirect calorimetry

Time frame: Before the surgery and at 6 and 12 month after

Cardio-metabolic profile parameters

postprandial plasma markers: We will assess: glycaemia (g/L)

Time frame: Before the surgery and at 6 and 12 month after

Cardio-metabolic profile parameters

CRP

Time frame: Before the surgery and at 6 and 12 month after

Vital parameters

Blood pressure

Time frame: Before the surgery and at 6 and 12 month after

Nutritional status: Blood vitamin

Blood vitamin status : For the research, we will focus only whether or not the participant has a deficiency in one of the vitamins measured (yes/no variable). The vitamins assessed are : \- Vitamin B12 (pmol/L) should be above 145 pmol/L

Time frame: Before the surgery and at 6 (except plasma fatty acid profile) and 12 month after

Nutritional status : Blood mineral

Blood mineral status: * Calcium (mmol/L) should be above 64 mmol/L * Phosphor (mmol/L) should be above 0.81 mmol/L * Magnesium (mmol/L) should be above 0.66 mmol/L * Sodium (mmol/L) should be above 136 mmol/L * Potassium (mmol/L) should be above 3.4 mmol/L * Chlore (mmol/L) should be above 98 mmol/L

Time frame: Before the surgery and at 6 (except plasma fatty acid profile) and 12 month after

Nutritional status : Plasma fatty acid

Plasma fatty acid profile

Time frame: Before the surgery and at 6 (except plasma fatty acid profile) and 12 month after

Nutritional status : Protein

Protein status

Time frame: Before the surgery and at 6 (except plasma fatty acid profile) and 12 month after

Average energy

Assessed using 3-day dietary recall randomly selected from the 7 days preceding the visits

Time frame: Before the surgery and at 6 and 12 month after

macronutrients intakes and proportions

Assessed using 3-day dietary recall randomly selected from the 7 days preceding the visits

Time frame: Before the surgery and at 6 and 12 month after

micronutrients intakes and proportions

Assessed using 3-day dietary recall randomly selected from the 7 days preceding the visits

Time frame: Before the surgery and at 6 and 12 month after

Mental health: Quality of life

Quality of life using the SF36 questionnaire SF36 - health status questionnaire - score from 0 to 100, score of 100 = excellent perceived health

Time frame: Before the surgery and at 6 and 12 month after

Mental health: Self-confidence

Self-confidence and self-efficacy using the GSES GSES: Generalized Self-Efficacy Scale - score of 10 to 40, score of 40 = strong confidence in one's ability to effectively manage different life situations and challenges

Time frame: Before the surgery and at 6 and 12 month after

Mental health: Depression

Depression with PHQ-9 PHQ-9: Patient Health Questionnaire -score from 0 to 27, score of 27=severe depression

Time frame: Before the surgery and at 6 and 12 month after

Mental health: Anxiety

Anxiety assessment using GAD-7 GAD-7: Generalized Anxiety Disorder - if score \>7 then anxiety disorders should be suspected

Time frame: Before the surgery and at 6 and 12 month after

Physical activity

Assessed using the short version of the IPAQ IPAQ: International Physical Activity Questionnaire - continuous daily energy expenditure score, high score means high AP The questionnaire allows the subject to be classified according to 3 levels of activity: inactive, moderate, high.

Time frame: Before the surgery and at 6 and 12 month after

Emotions: positive and negative

positive and negative emotion assessed using the PANAS scale PANAS: Positive Affectivity and Negative Affectivity Scale - 2 scores from 10 to 50 - positive affectivity score = 50 best, negative affectivity score = 50 worst

Time frame: Before the surgery and at 6 and 12 month after

Emotions: food phobias

food phobias using the FNS questionnaire FNS : Food Neophobia Scale -score from 10 to 70 - score of 70 = neophobia, i.e. less willingness to try new foods

Time frame: Before the surgery and at 6 and 12 month after

Emotions: loneliness

loneliness using the ESUL questionnaire University of Laval Loneliness Scale - score from 20 to 80, score of 80 = most pronounced feeling of loneliness

Time frame: Before the surgery and at 6 and 12 month after

Changes in stool consistency

Assessed using Bristol stool scale Bristol scale : 7 types of stools to choose from photo: type 1 = hard and lumpy stools, type 7 = completely liquid stools

Time frame: Before the surgery and at 6 and 12 month after

Changes in stool frequency

Assessed using Bristol stool scale : 7 types of stools to choose from photo: type 1 = hard and lumpy stools, type 7 = completely liquid stools

Time frame: Before the surgery and at 6 and 12 month after

Changes in gastrointestinal symptoms

Assessed using Bristol stool scale

Time frame: Before the surgery and at 6 and 12 month after

Grade of hepatic steatosis

Evaluation by FibroScan® but only for patients who had a FibroScan® performed before surgery.

Time frame: Before the surgery and at 12 month after

Grade of hepatic fibrosis

Evaluation by FibroScan® but only for patients who had a FibroScan® performed before surgery.

Time frame: Before the surgery and at 12 month after

Eating behaviour and preferences : Behaviors

Behaviors (emotional eating and cognitive restraint) using score from the DEBQ (Dutch Eating Behavior Questionnaire) a DEBQ : Dutch Eating Behaviour Questionnaire : 3 sub-scores: cognitive restriction, reactivity to external stimuli and emotionality from 1 to 5, score 5 = strong impact of eating behavior

Time frame: Before the surgery and at 6 and 12 month after

Hepatic metabolic flexibility

Assessed via the degree of alteration of MAMs (Mitochondia-Associated Membranes) in peripheral blood mononuclear cells (PBMCs), only for patients who had a FibroScan® performed before surgery.

Time frame: Before the surgery and at 6 and 12 month after

Safety parameters

thyroid function: Thyroid function is assessed based on TSH levels in mIU/L (should be above 0.4 mIU/L and below 4.8 mIU/L), 2. The assessment for the research is whether the measures are within the limits or not (yes/no variable).

Time frame: Before the surgery and at 6 and 12 month after

Compliance and follow-up of advice given during the intervention

Based on the three 24-hour reminders completed by participants before each visit, the dietitian will classify participants into three categories: good, average or poor compliance.

Time frame: until month 12

Eating behaviour during a standardised, filmed and validated ad libitum buffet: Meal microstructure

time spent selecting food at the buffet

Time frame: Before the surgery and at 6 and 12 month after

Eating behaviour during a standardised, filmed and validated ad libitum buffet: Meal microstructure

duration of ingestion

Time frame: Before the surgery and at 6 and 12 month after

Eating behaviour during a standardised, filmed and validated ad libitum buffet: Meal microstructure

ingestion speed

Time frame: Before the surgery and at 6 and 12 month after

Changes in stool consistency

Assessed using Likert scale Likert scale : 7 types of stools to choose from photo: type 1 = hard and lumpy stools, type 7 = completely liquid stools

Time frame: Before the surgery and at 6 and 12 month after

Changes in stool consistency

Assessed using gastrointestinal symptoms using GSRS Gastrointestinal Symptom Questionnaire - score 15 to 105, score 105=severe gastrointestinal symptoms

Time frame: Before the surgery and at 6 and 12 month after

Safety parameters

complete blood count

Time frame: Before the surgery and at 6 and 12 month after

Safety parameters

AST

Time frame: Before the surgery and at 6 and 12 month after

Safety parameters

ALT

Time frame: Before the surgery and at 6 and 12 month after

Safety parameters

gamma GT

Time frame: Before the surgery and at 6 and 12 month after

Safety parameters

bilirubin

Time frame: Before the surgery and at 6 and 12 month after

Safety parameters

alkaline phosphate

Time frame: Before the surgery and at 6 and 12 month after

Safety parameters

creatinine

Time frame: Before the surgery and at 6 and 12 month after

Safety parameters

uric acid

Time frame: Before the surgery and at 6 and 12 month after

Safety parameters

ionogram results: Sodium (mmol/L) which should be between 136 and 145 Potassium (mmol/L) which should be between 3.4 and 4.5 Chlorine (mmol/L) which should be between 98 and 107 Bicarbonates (mmol/L) which should be between 22 and 29

Time frame: Before the surgery and at 6 and 12 month after

Safety parameters

coagulation : prothrombin time

Time frame: Before the surgery and at 6 and 12 month after

Changes in stool frequency

Assessed using Likert scale

Time frame: Before the surgery and at 6 and 12 month after

Changes in stool frequency

Assessed using gastrointestinal symptoms using GSRS : 15 questions with answers from No discomfort at all at Very severe discomfort (7 levels)

Time frame: Before the surgery and at 6 and 12 month after

Changes in gastrointestinal symptoms

Assessed using Likert scale

Time frame: Before the surgery and at 6 and 12 month after

Changes in gastrointestinal symptoms

gastrointestinal symptoms using GSRS

Time frame: Before the surgery and at 6 and 12 month after

Eating behaviour during a standardised, filmed and validated ad libitum buffet: Meal microstructure

total meal duration

Time frame: Before the surgery and at 6 and 12 month after

Eating behaviour during a standardised, filmed and validated ad libitum buffet: Meal microstructure

number of bites per minute

Time frame: Before the surgery and at 6 and 12 month after

Eating behaviour during a standardised, filmed and validated ad libitum buffet: Meal microstructure

total number of bites

Time frame: Before the surgery and at 6 and 12 month after

Eating behaviour during a standardised, filmed and validated ad libitum buffet: Meal microstructure

bites by food type

Time frame: Before the surgery and at 6 and 12 month after

Eating behaviour during a standardised, filmed and validated ad libitum buffet: Meal microstructure

food choices

Time frame: Before the surgery and at 6 and 12 month after

Eating behaviour during a standardised, filmed and validated ad libitum buffet: Meal microstructure

Calorie intake consumed per minute of the buffet

Time frame: Before the surgery and at 6 and 12 month after

Safety parameters

ionogram results: Anion gap = (Na+ + K+) - (HCO3- + Cl-) (mmol/L) which should be between 12 and 20

Time frame: Before the surgery and at 6 and 12 month after

Endocrine, digestive or intestinal hormones

Blood sample to measure : Ghrelin pg/ml acylated ghrelin pg/ml

Endocrine, digestive or intestinal hormones

Blood sample to measure : GIP pmol/l total GLP-1 : pmol/L glucagon : pmol/L

Endocrine, digestive or intestinal hormones

Blood sample to measure : total PYY : ng/L

Endocrine, digestive or intestinal hormones

Blood sample to measure : leptin : ng/ml

Cardio-metabolic profile parameters

We will assess: insulin (mU/L)

Time frame: Before the surgery and at 6 and 12 month after

Cardio-metabolic profile parameters

We will assess: triglycerides (mmol/L), HDL (mmol/L), LDL (mmol/L), ApoB (mmol/L), sphingolipid (mmol/L) and unesterified fatty acid(mmol/L)

Time frame: Before the surgery and at 6 and 12 month after

Cardio-metabolic profile parameters

we will calculate: HOMA-IR (=insulin\*glycarmia/22.5) and the total cholesterol/HDL cholesterol ratio.

Time frame: Before the surgery and at 6 and 12 month after

Cardio-metabolic profile parameters

postprandial plasma markers: We will assess: insulin (mU/L)

Time frame: Before the surgery and at 6 and 12 month after

Nutritional status: Blood vitamin

Time frame: Before the surgery and at 6 (except plasma fatty acid profile) and 12 month after

Nutritional status: Blood vitamin

Time frame: Before the surgery and at 6 (except plasma fatty acid profile) and 12 month after

Nutritional status: Blood vitamin

Time frame: Before the surgery and at 6 (except plasma fatty acid profile) and 12 month after

Nutritional status : Blood mineral

Blood mineral status: * Iron (µmol/L) should be above 5.8µmol/L * Selenium (µmol/L) should be above 56µmol/L * Zinc (µmol/L) should be above 9.20µmol/L

Time frame: Before the surgery and at 6 (except plasma fatty acid profile) and 12 month after

Safety parameters

thyroid function: Thyroid function is assessed based on free thyroxine in pmol/L (should be above 11.9 pmol/L and below 21.9 pmol/L) The assessment for the research is whether the measures are within the limits or not (yes/no variable).

Time frame: Before the surgery and at 6 and 12 month after

Safety parameters

thyroid function: Thyroid function is assessed based on free triiodothyronine in pmol/L (should be above 3.1 pmol/L and below 6.8 pmol/L). The assessment for the research is whether the three measures are within the limits or not (yes/no variable).

Time frame: Before the surgery and at 6 and 12 month after

Cardio-metabolic profile parameters

Waist-to-hip ratio will be assessed

Time frame: Before the surgery and at 6 and 12 month after

Vital parameters

resting heart rate

Time frame: Before the surgery and at 6 and 12 month after

Safety parameters

coagulation : activated partial thromboplastin time

Time frame: Before the surgery and at 6 and 12 month after

Safety parameters

coagulation : fibrinogen

Time frame: Before the surgery and at 6 and 12 month after

Cardio-metabolic profile parameters

We will assess: total cholesterol (g/L)

Time frame: Before the surgery and at 6 and 12 month after

Cardio-metabolic profile parameters

We will assess: HbA1c (mmol/mol),

Time frame: Before the surgery and at 6 and 12 month after

Impact of a Pro-diversity Gut Microbiota Diet After a Bariatric Surgery on Gut Microbiota, Eating Behaviour and Sensory Function

Overview

Conditions

Interventions

Eligibility

Locations (3)

Outcomes

Primary Outcomes

Secondary Outcomes

Central Contacts