Riding a bike has brought me joy for as long as I can remember (after mastering the whole “no training wheels thing” as a kid…), but it’s been a while since I’ve had my own wheels to ride around town on. That all changed when I recently found the perfect “starter bike,” and just in time to ride along the Charles in the beautiful sunshine! I have also recently discovered that I like to ride my bike while listening to the “TED radio hour” podcasts to achieve the added bonus of doing a little learning while I pedal.
One of the episodes I listened to recently was titled “What is so special about the human brain?” and I found myself listening with raptured attention (while still being mindful to obey all traffic laws and stay aware of my surroundings) as the speaker discussed how our brains function, how they’ve evolved, and just how much more there is to be discovered about their complexities.
The most fascinating part of the podcast to me was when Suzana Herculano-Houzel, a neuroscientist at the Instituto de Ciências Biomédicas in Rio de Janeiro, discussed her research regarding what makes the human brain different from that of other creatures and how the evolutionary process allowed this to be so.
It turns out that it isn’t the size of our brains which determines how cognitively advanced we are (evidenced by the fact that creatures like elephants and whales have much larger brains than we do), but instead it’s the amount of energy that our brains consume. Although the human brain accounts for only ~2% of our body weight, but uses ~25% of all of the energy that our bodies requires to run daily. To illustrate this with an example, if you were to eat a ~2,000 calorie/day diet, 500 of those calories would be used solely to fuel your brain.
Why is it that the human brain requires so much more energy than our closely related counterparts? It’s due to the fact that almost 20% of the billions of neurons in our brain are located in the cerebral cortex – the area of the brain which allows us to plan ahead, reflect back, and learn from our mistakes. This 20% is significantly greater than our closely related cousins, the apes. In her TED talk, Suzana Herculano-Houzel discusses how this came to be, and the answer sparked great interest in my own “nutrition focused” brain. It turns out that in order to add new neurons, the brain requires added energy, so the increased number of neurons in our cerebral cortex is actually more “energetically expensive.” Apes eat a diet of raw foods consisting of bark, leaves, etc and spend ~8.5 hours/day gathering and eating food in order to meet their energy needs. If human beings were to eat in the same way, we would need to spend ~9.5 hours every single day focused on finding and eating food in order to maintain the brains we have today.
In order for our brains to evolve beyond that of an “ape brain,” our ancestors had to find a way to take in more calories than were available through just raw foods. How did they accomplish this? Through the advent of cooking! By cooking their food, they were able to access more energy by making the food softer and easier to chew and digest. This discovery allowed them to spend less time devoted to gathering food and eating while increasing their energy intake to allow for more neuron formation. The added bonus was that it freed up the majority of their days to allow for participation in much more interesting (and further brain stimulating) tasks. So by being able to increase our energy intake, we were able to literally grow our brains into more highly functioning tools AND allow for the freedom and flexibility for those brains to be put to good use and further developed. Definitely a positive reinforcement cycle!
All of this fascinating information left me with some “food” for thought. The above content is just one more reason to insure that your body and brain get the nourishment they need. Without adequate energy intake, our brains aren’t able to function optimally and quite literally “grow” to their highest potential. In addition, the brain picks up on this energy scarcity as a sign that food needs to become the main focus, so it makes sense that those caught in restrictive eating patterns feel they can think of nothing but food. Do yourself a favor and “free up” some of that brain space to take part in more interesting and fulfilling activities outside of eating – there’s a world of possibilities out there to discover!