Cravings and the Blame Game - Part 1: Why We Eat the Foods We Eat
You smell it before you even enter the room. That sweet and spicy aroma, you can practically feel the warm and taste the cheesy, saucy gooeyness before you even lay eyes on the beautiful creation. Mmmm, pizza. Pizza just left there on the break table just beckoning you in with a big ole free sign. Maybe you resist and spend the rest of the day at your desk with visions of pepperoni and mushrooms dancing through your head. Maybe you caved and gobbled down a slice or two and later you scolded yourself for being so “weak.” Whatever the case, that seemingly innocent pizza pie held all the power.
Sound familiar? If it does, you are definitely not alone. We often feel at the mercy of our cravings thinking if we just mastered that whole willpower thing, we would always eat our salads and be dang happy about it. Society definitely makes it seem that way with a new diet being broadcasted every Monday and proclamations of happy = skinny.
Let me say this loud and clear for the people in the back…
Our cravings, our visceral responses of salivation and longing are not issues, we’ve made up in our head but hardwired into our DNA. In Part 1 why caving for the chocolate cake for the umpteenth coworker’s birthday celebration would have given you an evolutionary advantage and how your hormones are key players in the satiety game. In Part 2 we’ll discuss why mom and dad might be to blame why you don’t like carrots and why water isn’t a bad thing to drink when you’re bored. In Part 3 I’m letting you know why you might want to start paying more attention to your gut bugs and how you can feel more in control when a craving strikes and learn to trust the wisdom of your body.
Sounds fun, right?
Grab yourself a cup of tea and let’s get into it.
Merriam-Webster dictionary defines hunger as “a craving or urgent need for food or a specific nutrient.”(1) This definition notably does not specify whether that need is physiological or psychological, suggesting that there are more complex reasons why we eat the foods we eat.
In our history as a human being, those who ate and ate a lot survived. Animals who eat and drink hold a survival advantage and are able to produce more offspring.(2) People who were able to overeat and ignore feelings of fullness were able to bulk up and store fat to survive the next famine.(3)
The world we live in now looks very different, with every type of food available no matter the season but our body is still programmed the same way. We now worry less about hunger and more about satiety. I love the definitions of satiety – “the quality of being fed to or beyond capacity” and “the revulsion caused by overindulgence.”(4) I think we can all appreciate that very fine line from savoring every last bite to jean-button-popping overstuffed discomfort.
The primary tastes we sense are sweet, sour, salty, bitter, and umami. We have an innate preference universally for sweet, salty, and milk. The preference for sweet is strong even in cultures where sweet is not a customary taste. It is almost never rejected.(5) Children especially seek sweet things because they are growing and sweet things often signal higher calories. When these foods are given as a reward, say an ice cream cone for an A on an exam, this association of sweet and pleasure is heightened.(2) Sweet tastes activate the reward center of our brain and with sweet foods available everywhere, it’s no wonder we struggle to resist a tempting baked good. (6)
DRIVEN TO EAT
So what’s happening when we see something we want to eat? First, the mesolimbic portion or the reward center of our brain gets excited which signals the vagus nerve to yell to the stomach to start secreting digestive juices. The pancreas gets started on pumping out insulin while the liver is on alert to deal with the influx of sugar and fat that’s coming the body’s way.(3) This process can occur even when we haven’t taken a bite of that yummy brownie yet, just the pure sight or smell can start it!
Our main hormones involved in hunger and satiety are insulin, cholecystokinin (CCK), and ghrelin. Insulin is our satiating agent that decreases appetite. CCK lets us now when it is time to stop eating, but it’s signaling does not last long which can lead to overeating especially if we’re fueling with distractions. Ghrelin is our main hunger hormone that lets us know when it’s time to eat and the reason we get hangry. If you get in the habit of reaching for a snack at 3 PM every day, ghrelin’s got you on that schedule.(3) Lack of sleep can cause ghrelin to increase and is correlated with an increased consumption of calories from sweets.(7) I think we all know when we get a bad night of sleep the munchies seem to hit us in full force.
Our central nervous system also plays a role in our feelings of fullness. In charge of regulating these sensations is the hypothalamus, a region of the brain that produces hormones specifically involved in satiation. The ventromedial hypothalamus (VMH) lets you know when it can’t take another bite and it’s time to put down the fork. Your lateral hypothalamus when stimulated lets you know it’s feeling hangry and it’s time to eat.(2)
As you can see, from an evolutionary standpoint and biological standpoint, your body is responding in the way it was created. Your cravings are resulting from the complex interaction of your environment, hormones, and genetics.
Stay tuned for Part 2 where we’ll dive a little deeper and explore the other factors at play for why we crave the foods we do!
1. Hunger | Definition of Hunger by Merriam-Webster. https://www.merriam-webster.com/dictionary/hunger. Accessed October 30, 2018.
2. Logue A. The Psychology of Eating and Drinking. Fourth. New York, NY: Routledge; 2015.
3. The Science of Appetite - The Science of Appetite - TIME. http://content.time.com/time/specials/2007/article/0,28804,1626795_1627112_1626670,00.html. Accessed October 29, 2018.
4. Satiety I Definition of Satiety by Merriam-Webster. https://www.merriam-webster.com/dictionary/satiety. Accessed October 30, 2018.
5. White, W. Psychology of Eating: Taste and Smell. Presented: October 2, 2018; National University of Natural Medicine.
6. Gut–brain nutrient signaling. Appetition vs. satiation - ScienceDirect. https://www-sciencedirect-com.nunm.idm.oclc.org/science/article/pii/S0195666312001936. Accessed October 30, 2018.