If you’ve never read “The Hungry Brain” by Dr. Stephan Guyenet I suggest you put it on your list. It’s one of the easiest reads to understand how our brain works when it comes to food. Dr. Guyenet is a neuroscientist and has taken one of the most complex instruments in the universe, the human brain, and simplified how it helps us make decisions regarding our eating habits. You want to be healthier? Read this book! Below are my first 5 key “take aways” from his book.
- The brain (shocker) is 100% responsible for our appetite, eating behavior, physical activity, and body fat. Dr. Guyenet describes the brain as having two systems. System 1 is fast, effortless, intuitive, and nonconscious (ex. Buying a Chick-Fil-A® chicken biscuit on your way to work). System 2 is slow, effortful, rational, and conscious (ex. Grocery shopping and prepping your meals for the week). Unfortunately, after millions of years of evolution our brains are wired to the point where System 1 wins more often on a daily, even hourly, basis.
Some would argue we know more about the universe than we know about our own brain
This idea is scarier than one might want to admit. Without boring you with all the science, our brain has the ability to make decisions for us without our conscious input. This includes unhealthy and risky decisions. Sure, we have to see something, smell something, etc. but our brain can instantaneously calculate out whether or not the decision to get in the car and drive to the local Chinese takeout spot is worth our time and effort. This gives substantial argument to the idea that we don’t have “free will” when it comes to our food choices. Have you ever eaten something you knew was unhealthy for you but you ate it any way? Even when you weren’t hungry? Yep, me too. Don’t get me wrong, we have free will in what we choose to eat, just like everything else in life, but due to our evolution we are wired to consume calorie dense, fatty, starchy, and sugary foods. Basically, we’re fighting against millions of years worth of adaptation.
- Calories are STILL king! Dr. Guyenet puts it in terms that we’ve known for a very long time:
Change in adiposity (body fat) = Calories IN – Calories OUT
The commonly held belief, even held by myself until reading this book, was to reduce your calorie intake by 500 kcal per day and you should lose roughly 1 pound of fat per week. UNFORTUNATELY, this has been shown to be inaccurate in predicting fat loss for the long-term because, as we lose weight, our body’s energy needs change. We burn fewer calories at rest if we get smaller and burn more if we get bigger. In the end, it’s OVERALL calorie consumption over the long-term (months/years, not days/weeks) to change overall body composition that is sustainable.
So, how many calories do we need to cut out to lose body fat? Only a 10% change in calorie consumption per day is the difference between being a lean individual or overweight/obese individual. If you need to consume 2500 kcal per day to maintain your weight then the obese individual beside you only needs to consume 2750 to gain weight. That’s the difference of 2 beers every day!
10% difference in calorie consumption makes a BIG difference
- More varied & palatable food choices lead to overeating (make it free and it’s borderline irresistible). A study conducted by Dr. Ravussin in the early 1990s showcased an experiment where individuals could pick their own foods from a vending machine (everything was free) and noticed everyone ate nearly double the amount of calories they needed on a daily basis. This situation was termed opportunistic voracity: given the opportunity we will take it, even if we don’t need it.
The scary part is that we currently live in a society full of opportunistic voracity. Everywhere we go there are thousands and thousands of food choices and they’re delicious! We don’t have to be in one of Dr. Ravussin’s experiments. We are already living the experiment.
- Dopamine (“pleasure chemical”) is a massive driving factor behind our overeating, but not for reasons you might think. Dopamine is strongly related to the release of endorphins, which some would argue is the true “pleasure chemical”. If that’s the case then why is dopamine getting the blame? It’s because dopamine is the “learning chemical” according to Dr. Guyenet.
Endorphins increase when we like what happens, whether it’s good or bad for us
As we grow up and learn what makes us feel good, such as eating a delicious pizza or winning the 100m race in high school, the VTA (ventral tegmental area) of our brain says, “I like that, I’m going to increase the dopamine response to that feeling so I’ll be more inclined to do it next time.” As you can see, the amount of dopamine associated with an activity drives us to do it again or not do it again. Growing up most of us didn’t associate eating broccoli, while good for us, with pleasure. Hence, this is why we learned to crave foods that are sugary, starchy, fatty, and carbohydrate dense.
- Many of us are overweight because food, or the sight/smell of food, is within reach. That’s right, if it’s within arms length your waistline will grow. Simply being further from unhealthy foods goes a long way to shrink our waistlines. This goes back to the first point in this article where D. Guyenet points out that the brain instantaneously makes a decision whether or not something is worth our effort.
One study tested the “threshold” of an impulse for food based using distance. In the study, Hershey’s ® kisses were used in an office setting. The kisses were located on the desk, in a drawer, or on top of a filing cabinet 6 feet away. On the days where the candy was on top of the filing cabinet the employees ate less than 4 kisses per day, compared to 9 or more per day when the candy was on the office desk.
There’s a reason mom always put the cookie jar on top of the refrigerator
Dr. Guyenet mentions you can use this knowledge to improve your health one day at a time and it’s arguably the easiest thing to do. You control what goes in your pantry, refrigerator, and freezer. Start off by NOT buying the foods that are making you fatter! If the temptation is not there then it’s much easier to avoid it. Keep tasty treats in a place that’s not so easy to reach (i.e. top cupboard that requires a stepping stool). Stay tuned for more info next week on how we can improve our relationship with food and be healthier
You can get Dr. Guyenet’s book HERE
STAY FIT MY FRIENDS!