Our brains form, strengthen, and prune synapses throughout our lives (it’s happening in your brain right now as you form new memories from reading this book) but by far the most active period is in childhood, when we’re soaking up the world around us. Work by Christopher Kuzawa and colleagues has shown that in children three to seven years old, the brain accounts for over 60 percent of BMR, three times more than in adults. So much energy is channeled to the brain during these early critical years that it actually slows down growth in the rest of the body.
