Rewilding
Return your body to the wild, self-willed state it was designed for over 250,000 years.
- Difficulty
- Moderate
- Time to result
- ~months to results
- Steps
- 4
- Confidence
- 78%
Rewilding, which Jansen calls the ultimate form of biohacking, means returning the body to its wild, self-willed state and undoing domestication. Since human biology has been stable for about 250,000 years, it never adapted to fast food or synthetic molecules. He champions cold training in the tradition of Wim Hof, taking only cold showers and swimming in the sea even in winter, because cold water benefits skin, vasodilation, cardiovascular and neurological health, and activates brown fat. Diet is individual: he has cycled through raw vegan, paleo, vegetarian, and macrobiotic, ultimately landing on a values-driven near-keto mix.
Origin
Studying Wim Hof and Tim van der Vliet and prescribing to evolutionary theory, Jansen concluded that the body is designed for a wild environment and adopted cold-only bathing and ancestral eating patterns, experimenting across many diets over years to find what suited his biology and values.
Core principles
- 01Human biology has been essentially unchanged for ~250,000 years and has not evolved for fast food or synthetic molecules.
- 02Cold water exposure aids skin, vasodilation, cardiovascular and neurological health, and activates brown fat.
- 03Undoing domestication means eating, bathing, and moving the way the body is designed to.
- 04The optimal diet is individual and tied to your values, not a universal prescription.
How to run it
- 1
Adopt cold water bathing
Stop taking hot or even warm showers and switch to cold water, which supports skin, circulation, cardiovascular and neurological health.
Pro tip Cold exposure activates brown fat, improving thermogenesis.
Watch out People with heart conditions should get medical clearance before cold immersion.
- 2
Add cold immersion and breathwork
Swim in a lake, river, or sea and pair it with Wim Hof-style breathing and cold training.
Watch out Never do breath holds in or near open water alone.
- 3
Eat what your body evolved for
Cut synthetic molecules and fast food your body never adapted to, and eat closer to ancestral patterns.
- 4
Find your individual diet
Experiment across dietary approaches; the right one depends on your biology, preferences, and value system.
Pro tip There is no universal best diet; align it with what you want to achieve and your values.
In the wild
Living 100 yards from the beach, Jansen swims in the sea even in winter and never takes a hot or warm shower, even in Moscow.
→ He reports being energized and connecting to the wild, free version of himself his biology was designed for.
Common mistakes
Seeking a universal diet
Every biohacking process is individual; the best diet depends on your biology and values, so copying someone else's plan often fails.
Staying fully domesticated
Sedentary comfort, hot showers, and processed food fight against a body built for a wild environment, accumulating trouble over time.
Is it for you?
Best for
Biohackers wanting to align lifestyle with evolutionary biology and build cold tolerance.
Not ideal for
People with cardiovascular conditions who should not do cold immersion without medical clearance.
From the transcript
“Rewilding is... you're basically going back to what your body is meant to be doing.”
“I never take a hot shower or even a warm shower even when I'm in Moscow... cold water all the time.”
From the episode
Peter Jansen: Biohacking Your Brain and Body
Peter Jansen