Study of the Effects of Overfeeding on Glucocorticoids in Lean and Obese Subjects
Condition: Overweight and Obesity
MeSH terms: Overweight
Study type: Observational

Summary: 
      Investigators suggest that in lean subjects cortisol increases in response to overfeeding and
      that this increase is blunted in obese subjects. A group of 18 male healthy lean subjects and
      another group of 18 male healthy obese subjects will undergo a high-calorie meal test. Prior
      to the meal intake, an indirect calorimetry, bioelectrical impedance, heart rate variability,
      a fasting blood sample and a perceived stress questionnaire will be assessed. After intake of
      the study meal, blood tests will be performed in order to measure the secretion of cortisol,
      glucose and lipid metabolism and inflammatory markers. Indirect calorimetry will be assessed
      again 60 and 180 minutes after the meal intake.
    

Detailed description: 
      Obesity is one of the most serious health problems in the 21st century. High energy food and
      a sedentary lifestyle are driving the current obesity pandemic. These factors activate the
      hypothalamic-pituitary-adrenal (HPA) axis, the key regulatory pathway of energy homeostasis.
      Activation of the HPA-axis leads to secretion of glucocorticoids from the adrenal glands,
      which control energy homeostasis by mobilizing and redistributing energy substrates.

      Animal models of obesity have shown that glucocorticoids play a key role in the development
      of the metabolic syndrome. However, studies in humans yielded conflicting results. These
      studies have a major limitation in common. They do not consider glucocorticoid rhythmicity
      but rather investigate a snapshot of glucocorticoid secretion. Rhythmicity, however, is
      crucial because already minor glucocorticoid phase disturbances cause disease and could
      contribute to obesity.

      Interestingly, excessive food intake may increase cortisol levels in healthy subjects . The
      consequence of this food-induced cortisol peak is not understood, but it may be key to
      restoring energy homeostasis after a meal. Whether the food-induced cortisol peak in obese
      subjects is disturbed is not known

      With this study, investigators aim to better understand the role played by glucocorticoids in
      the origin of overweight and obesity. Researchers will investigate, in lean and obese
      subjects, whether the pulsatile release of cortisol increases after intake of a high-calorie
      meal. 36 subjects will take part in the study: a group of 18 male lean subjects and a second
      group of 18 male obese patients.
    

Intervention name(s): High-calorie meal
Intervention type(s): Other
Intervention description(s): Intake of a high-calorie meal (2500-3000 calories) within 15 minutes.
Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Community sample. The obese group will be both a community and a clinical sample.
      
Biospecimen description: 
      Blood samples
    
Keywords: obesity; overweight; cortisol; overfeeding; glucocorticoids