Mechanisms of Fasting Induced Reduction in Energy Expenditure

Mechanisms of Fasting Induced Reduction in Energy Expenditure - FIRE Trial

Fasting reduces the energy consumption of the human body. The extent of this adaptation varies significantly between different individuals. The aim of this research project is to investigate how this adaptation of the metabolism is regulated by the body. For this purpose, we will first measure how the so-called basal metabolic rate of the body reacts to a short-term fasting of 24 h in a preliminary study. Those subjects with a particularly pronounced and those subjects with an only slightly pronounced reaction of the basal metabolic rate will be invited to the main study.

Here, in random order (24 h fasting vs. 8 h fasting), the following is compared

• how the basal metabolic rate of the body reacts to the reduced energy intake.
• how the energy metabolism increases after a test meal
• what role in particular the thyroid hormones play in this adaptation. In addition, a sample of the subcutaneous adipose tissue is taken in each case and it is examined how the regulation of metabolic processes at the cellular level.

The extent of this adaptation varies significantly between different individuals. The aim of this research project is to investigate how this adaptation of the metabolism is regulated by the body. For this purpose, we will first measure how the so-called basal metabolic rate of the body reacts to a short-term fasting of 24 h in a preliminary study. Those subjects with a particularly pronounced and those subjects with an only slightly pronounced reaction of the basal metabolic rate will be invited to the main study.

Inclusion Criteria:

• Age: 18 to 40 years
• Body mass index 18.0 to 27.0 kg/m²
• Exclusion Criteria:
• Chronic conditions necessitating medical treatment (e.g., renal failure, hepatic dysfunction, cardiovascular disease, diabetes mellitus),
• Known or suspected non-compliance, drug or alcohol abuse,
• Inability to follow the procedures of the study
• Participation in another study with investigational drug within the 30 days preceding and during the present study,
• Previous enrolment into the current study,
• Enrolment of the investigator, his/her family members, employees and other dependent persons,
• Hypothyroidism or hyperthyroidism
• Pregnant, breastfeeding and menopausal women