The Hibernation Response
A metabolic survival state where the body suppresses thyroid function and slows metabolism to conserve energy in response to perceived threats like starvation, stress, or trauma.
Deep Dive
When your body perceives a threat — such as chronic calorie restriction or sustained stress — it shifts into a state of metabolic conservation known as the Hibernation Response. This is not a disease or a dysfunction. It is an ancient survival mechanism, hardwired into your DNA, designed to keep you alive when resources are scarce.
Evolutionarily, this kept our ancestors alive during famine. The body down-regulates thyroid output, increases Reverse T3 (the 'blocking' thyroid hormone), and shifts energy away from non-essential processes like fat burning, muscle repair, and reproduction. Today, the same mechanism is triggered not by actual famine but by chronic dieting, excessive exercise, sleep deprivation, and unrelenting psychological stress. The result is 'unexplained' weight gain, crushing fatigue, and a metabolism that seems broken.
Key signs that you may be stuck in the Hibernation Response include: a basal body temperature consistently below 97.8°F (36.5°C), elevated Reverse T3 on blood work, and an inability to lose weight even on very low calories. Paradoxically, eating less and exercising more only deepens the hibernation state.
The fix is counterintuitive: you cannot starve your way out of hibernation. You must signal safety to the body by eating enough of the right nutrients — adequate protein, healthy fats, and targeted micronutrients that support thyroid conversion and adrenal recovery. Only when the body believes the famine is over will it release the metabolic brake.