NutrImmune: Precision Nutrition to Improve Immunity in Individuals With Obesity

Obesity is a complex health condition defined by the World Health Organization (WHO) as an excess of body weight that may be harmful to health. It leads to other diseases such as type 2 diabetes or cardiovascular diseases, commonly referred to as "co-morbidities." Among these, it is known that obesity increases the risk of developing infectious diseases and of these diseases progressing to severe stages. During the COVID-19 pandemic and the 2009 H1N1 influenza epidemic, a rise in severe infection cases was observed in people with obesity. A part of people with obesity exhibits certain markers on the surface of their immune cells, which are known to cause immunosuppression when present in high numbers, thus increasing the risk of developing infectious diseases. Investigator teams found that after bariatric surgery and a calorie-restricted diet for weight loss, patients with obesity can improve the levels of these immunity-related markers. Moreover, the choice of foods consumed contributes to strengthening the immune system and immune functions of individuals, both directly by influencing inflammation and indirectly through the microbiota. However, to date, there are no dietary recommendations specifically designed to help people with obesity improve their immune response. Therefore, this study aims to compare different dietary recommendations intended to improve immune status, with or without calorie restriction, during 3 months, in individuals with obesity (BMI ≥ 30 kg/m²) and impaired immunity. Over 6 months (3 months of nutritional intervention and 3 months of follow-up), investigators will collect extensive information through biological samples, measurements and questionnaires to compare the different dietary interventions studied and to understand the mechanisms behind the results obtained.

Inclusion Criteria: * 30≤BMI\ 0, indicating a pro-inflammatory dietary potential * Affiliation with a social security scheme or beneficiary of such a scheme; * Effective contraception for women with ability to have children * Stable weight for at least 3 months (+/- 5% of total body weight) * In the opinion of the investigator, the subject has adequate support to comply with the entire study requirements as described in the protocol (i.e. ability to move to and from trial site, to understand and fill in the questionnaires, use the app; attend the scheduled visits, full understanding of the protocol) * Do not follow an exclusive diet (i.e. vegan, vegetarian, or diet without gluten or lactose) * Living at maximum 1 hour from clinical trial site * Willingness to not change physical activity level for the whole duration of the study. * Willingness not to perform any other weight-loss approaches. * Agreement to adhere to Lifestyle Considerations throughout study duration * For women of childbearing potential, a negative urinary pregnancy test is required General non-inclusion criteria: * Persons subject to a safeguard of justice measure * Persons without valid health certificate(s) in case of governmental measures in exceptional epidemic situations * Persons under legal protection (guardianship, curatorship) * Persons unable to use the study applications after a brief introduction or no access to a mobile phone or tablet with Bluetooth and internet access; * Persons with devices with previous iOS or Android operating systems that cannot run the applications, given that use of the IPICS-app (TOUVA) is necessary for the study; * Persons without a freezer and/or reluctant to store biological samples inside; * Tobacco (or vaping equivalent) consumption \> 5 cigarettes per day. * Pregnancy or breastfeeding in women of childbearing potential * Alcohol consumption exceeding 30g alcohol/day * Claustrophobia for indirect calorimetry. * Needle or blood phobia Medical non-inclusion criteria: * Usage in past 3 months : Antibiotics, Probiotics, Prebiotics, Systemic corticosteroids, Immunosuppressives * Laxative usage in past 2 months * PPI (Proton pomp inhibitor) usage in past 2 days * Conditions that alter both inflammatory and immune profile and induce biases in results interpretation * Uncontrolled thyroid disease, history of musculoskeletal, autoimmune, or neurological disease, as well as abnormal kidney and liver function tests (\>2 times upper reference range limit) * Presence of active chronic inflammatory disease, autoimmune disease requiring immunomodulatory treatment, known immunodeficiency, active malignancy, active chronic infection, or ongoing immunosuppressive treatment likely to significantly alter the immune parameters under investigation. * Presence of type 2 diabetes or uncontrolled cardiovascular disease (Stable obesity-related comorbidities, including hypertension, dyslipidemia, and stable cardiovascular disease, are not considered exclusion criteria). * Major mental disorders * Severe eating disorders based on detailed medical history, clinical examination and expertise of the investigating physician, trained in nutrition. * The use of medication or physical conditions interfering with the study outcomes, at the discretion of the investigating physician * Infectious episode in the month prior to inclusion * Allergy or intolerance to any of the components of the study devices and products * No contraindications to taking oral nutritional supplements, such as severe swallowing disorders or impaired consciousness, and non-functional digestive tract Exclusion Criteria: * Health conditions or treatments interfering with the protocol outcomes or procedure, depending on the situation, postponement of visits may be considered at the discretion of the physicians investigators; * Withdrawal of consent * Appearance of a non-inclusion criterion; depending on the situation, postponement of visits may be considered at the discretion of the investigating physicians; * Lost to follow-up