Timing of Caloric Intake, Diet-induced Thermogenesis and Hormonal Pattern
Condition: Diet-induced Thermogenesis
Study type: Interventional

Summary: 
      The investigators aim at analyzing whether eating a standard meal in the evening (at 8:00 pm)
      determines in the same individuals a lower diet-induced thermogenesis (DIT) and a different
      hormonal response than the consumption of the same meal in the morning (at 8:00 am).

      The primary outcome is: the intra-individual variation in DIT after the evening and morning
      meal consumption.

      The secondary outcomes are the intra-individual variations in glucose, triglyceride, insulin,
      free fatty acids, leptin, glucagon-like peptide-1, acylated ghrelin, adrenalin, noradrenalin,
      after the evening and morning meal consumption.
    

Detailed description: 
      Twenty healthy volunteers (ten males and ten females) are recruited among students and
      graduates attending the Department of Medical Sciences of Turin (Italy) to take part to this
      randomized cross-over trial.

      Participants randomly receive first the standard meal at 8:00 am and the week after the
      standard meal at 8:00 pm or vice versa. Eight-h before the meal (respectively at 12:00 pm or
      at 12:00 am), the participants receive the same standard meal (without protein
      supplementation) at their home, and then are asked to spend in bed the following 6 hours. A
      24-h urine collection is collected the day before each test in order to determine total
      urinary nitrogen excretion.

      The standard meal consists of: 100g white bread, 100g ham, 50g cheese, 125g yogurt, 200ml
      fruit juice, plus 25g protein supplement. The participants must consume each meal in 25-30
      minutes.

      A 30-min basal calorimetric (Deltatrac II) exam is performed. Participants remain in a supine
      position but awake and motionless on a hospital bed during the whole period, except during
      the meal, when they can sit to eat. At 8:00 am (or pm), the participants consume the meal,
      and then rest in a supine position for 90 min. Then, a second 60 min-calorimetric evaluation
      is done. From the first calorimetric exam (the basal) until the end of the second
      (post-prandial) blood samples are drawn every 30 min. The same time schedule is adopted in
      the case of the morning meal (at 8:00 am) and the evening meal (at 8:00 pm).

      The random sequence (morning/evening, evening/morning meal) is computer-generated, using
      blocks of different lengths in random order.

      The following are measured: weight, height, waist circumference, and at baseline and every
      30-min during the morning and evening tests: glucose, triglyceride, insulin, free-fatty
      acids, leptin, glucagon-like peptide-1, acylated ghrelin, adrenalin, noradrenalin.
    

Intervention name(s): calorimetric exam after a standard meal
Intervention type(s): Other
Intervention description(s): The calorimetric and metabolic responses to identical meals (a high-protein, low-carbohydrates meal) consumed in the morning (8:00 am) and in the evening (8:00 pm) are measured in healthy volunteers, after standardizing diet, physical activity level, duration of fast and resting
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: diet-induced thermogenesis; glucose; respiratory quotient