Why Your Brain Grew While Your Gut Shrank?

Why did the human brain grow while the gut shrank? Discover how cooking, fire and the expensive tissue hypothesis explain human brain evolution, brain energy use and why humans have big brains. Your brain is 2% of your body weight but burns about 20% of your energy. So where did that energy come from? In this video we follow the trade-off behind human evolution: a bigger brain, a smaller gut, and the food, fat and fire that paid for it. IN THIS VIDEO Why the brain is the most expensive organ you own How human and chimp guts differ The expensive tissue hypothesis (Aiello and Wheeler, 1995) Why cooked food let our digestive system shrink The 2011 twist: fat, not gut size, tracks brain size across mammals Why human babies are so chubby Why you get foggy when hungry and sleepy after a big meal SOURCES (check before publishing) Aiello and Wheeler (1995), The Expensive-Tissue Hypothesis Navarrete et al. (2011), Nature, brain size and fat across mammals Pontzer et al. (2016), Nature, energy use in humans and apes Kuzawa et al. (2014), PNAS, brain energy use in childhood Organ et al. (2011), PNAS, chewing time and cooking Richard Wrangham, Catching Fire WATCH NEXT Why Do Humans Cook Food But Animals Don't? [ Subscribe for more visual explainers on how things evolved and happened. #HumanEvolution #BrainEvolution #2DExplainer