Study of the Intestinal Microbiota During a Real Life Dietary Intervention in Subjects With Overweight or Obesity
Condition: Overweight and Obesity
MeSH terms: Obesity; Overweight
Study type: Observational

Summary: 
      Worldwide, 13% of the population had obesity in 2016 and overweight and obesity are
      recognized as the fifth leading risk factor for death (roughly 5 million deaths per year). In
      the United States alone, a recent study predicts that over half of the population will have
      obesity in 2030. At the global level, overweight and obesity are also estimated to account
      for 44% of diabetes, 23% of heart disease and between 7% to 41% of cancer cases, in addition
      to numerous other pathologies, including neurological disorders. While obesity and overweight
      are classified as a general disease (i.e. a body mass index (BMI) above 25 kg/m2 or 30 kg/m2,
      respectively), there are large variabilities between classifications of obesity observed. For
      example, sub-populations of obesity present either a rapid or delayed onset of other chronic
      diseases, such as diabetes or cardiovascular disease.

      Many studies show that lifestyle interventions are effective in improving overweight and
      obesity through weight loss, but with very large inter-individual variability, especially in
      the long-term. These interventions and the respective observed weight loss are also shown to
      reduce the risk of other cardiovascular or metabolic diseases, demonstrating the importance
      of weight loss for future quality of life Interestingly, there is a large variation in weight
      loss when implementing the same dietary or lifestyle changes, even when many factors are
      accounted for in clinical studies. Similar variable weight loss or metabolic responses are
      also observed for other obesity treatments, such as pharmaceutical or surgical interventions.
      Therefore, in order to prevent and treat overweight and obesity, it is critical to progress
      in the understanding of individual variations in responses (trajectories) to weight loss
      programs.

      While biological, environmental, and behavioral factors indeed drive personal responses,
      recent advances have allowed more insight into how the human body processes these stimuli,
      namely through microorganisms inhabiting the gastrointestinal tract. Over the last 10 years,
      the gut microbiota, the 100 billion bacterial cells inhabiting our intestines, has emerged as
      a recognized factor contributing to our health. Given its access to the food and medicine
      consumed by an individual, the gut microbiota can be seen as a "super integrator" highly
      sensitive to our environmental and lifestyle changes. Accumulating evidence has highlighted
      that the gut microbiota translates these environmental changes by altering its diversity of
      bacteria or functions and producing molecules that interact with organs and the brain.

      As part of a weight loss program conducted within the standard of care in a network of
      clinical centers across France, the investigators set out to establish a cohort to examine
      the relative contribution of clinical, nutritional, and lifestyle factors related to
      individual's weight loss success with an emphasis on evaluating the gut microbiome of
      individuals.

      Within this context, the investigators are testing whether an individuals' microbiota profile
      before the real-life dietary intervention influences weight loss responses and changes in
      metabolic health parameters to a standardized weight loss diet.
    


Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        All individuals who meet the various inclusion criteria as part of the routine care
        activity of French RNPC centers
      
Biospecimen description: 
      Stool samples