Study of How Fasting Affects Energy Use and Metabolism in Adults Aged 18 to 40

What this Trial Is About

Researchers are investigating how the bodys metabolism adapts to fasting by studying changes in the basal metabolic rate, which varies significantly among individuals. The project first measures the bodys metabolic response to a 24-hour fast in a preliminary study. Participants showing either a strong or weak metabolic response will then be invited to the main study to further explore these differences and the role of thyroid hormones in this adaptation. In the main study, participants undergo two fasting periods in random order one lasting 24 hours and another lasting 12 hours. After each fasting period, researchers measure how the basal metabolic rate responds to reduced energy intake and how energy metabolism changes after a mixed meal test. Additionally, samples of subcutaneous fat tissue are taken to examine cellular-level metabolic regulation. Participants will be involved in fasting sessions followed by metabolic assessments including indirect calorimetry to measure energy expenditure, blood tests for thyroid hormone levels, and respiratory quotient measurements. The main outcome is the change in energy expenditure 60 minutes after the test meal. The study includes a preliminary screening phase and a main randomized phase, with safety monitored throughout. Participation involves multiple visits and metabolic testing over the course of the study.

Mechanisms of Fasting Induced Reduction in Energy Expenditure