I've been reading Welcome to Your Child's Brain, I think this passage explains M prodigious eating:
[An adult's] mature brain, ...uses 17 percent of the body's total energy though it accounts for only 3 percent of the body's weight. ...From ages three to eight, children's brain tissue uses twice as much energy [due to synapse building and maintenance] as adult brain tissue. A five-year-old child weighing forty-four pounds (twenty kilograms) requires 860 calories per day, and fully half of that energy goes to the brain.I was joking with Drew that we should stop feeding M in case she gets too smart for us.
