Chris turns to longevity doctor Peter Attia to find out how changing his eating habits can help his quest for longevity. Ironically, the answer is to eat no food at all for four long days. If he can bear the hunger, fasting will unlock his body's own anti-aging powers and give Chris the edge he needs when he tries to hunt for his next meal... by spearfishing off the Great Barrier Reef.

Chris has always worked to keep his body healthy; now it's time to start looking after his brain. Neurologist Dr. Sharon Sha challenges him to go off-grid into the wilderness without a GPS or map. Teaming up with his buddy, First Nations artist Otis Hope Carey, Chris will need to tune into nature to navigate through Otis's remote ancestral homeland. The hike stirs up Chris's most precious memories.