Fasting for different lengths of time affects how fast your body burns energy, and fasting too often can slow it down instead of speeding it up.
Scientific Claim
Prolonged or frequent fasting can cause a decrease in metabolic rate after an initial increase.
Original Statement
“When you compare 12-hour fasts, 24-hour fasts, 36-hour fasts, 72-hour fasts, you can actually see where 168 goes wrong and why it eventually slows down the very metabolism that you're really trying to speed up.”
Context Details
Domain
nutrition
Population
human
Subject
prolonged or frequent fasting
Action
causes
Target
decrease in metabolic rate after initial increase
Intervention Details
Evidence from Studies
Supporting Evidence (1)
This study measured metabolic rate changes during 12, 36, and 72 hours of starvation in 29 healthy subjects. It found a transient increase in metabolic rate peaking at 36 hours followed by a decline, which directly supports the claim that prolonged fasting can cause metabolic rate to decrease after an initial increase. The study specifically observed that metabolic rate increased by about 6% at 36 hours but then decreased as fasting continued beyond that point.