When people eat much less for a few weeks, their body burns fewer calories each day, and part of that is because the body slows down on purpose to save energy.
Scientific Claim
Caloric restriction for 3 weeks results in a 266-calorie per day reduction in resting metabolic rate, with approximately half of this reduction due to adaptive thermogenesis.
Original Statement
“In that short window, their resting metabolic rate tanked by 266 calories per day. In 3 weeks, their daily metabolic rate went down 266 calories per day. Almost half of that was adaptive thermogenesis, meaning that the body voluntarily slowed itself down to survive. They lost 5% of their muscle mass in 3 weeks, which further dropped their metabolism.”
Context Details
Domain
nutrition
Population
human
Subject
caloric restriction
Action
results in
Target
266-calorie per day reduction in resting metabolic rate with adaptive thermogenesis
Intervention Details
Evidence from Studies
Supporting Evidence (2)
While this study focuses on shorter fasting periods (up to 72 hours), it documents metabolic changes that support the concept of adaptive thermogenesis. The study found that metabolic rate increased initially but then decreased with prolonged fasting, which aligns with the claim about metabolic rate reduction during energy restriction. However, the specific 266-calorie reduction figure mentioned in the transcript appears to reference a different study not explicitly listed in the evidence links.
This study examined long-term calorie restriction in humans and found changes in metabolic markers that suggest adaptive responses to reduced energy intake. While the study doesn't provide the specific 266-calorie reduction figure mentioned in the transcript, it demonstrates that the body adapts to reduced caloric intake by altering metabolic processes, which supports the concept of adaptive thermogenesis as a response to prolonged energy restriction.