Having a food craving is, scientifically, not the same as feeling hungry. Now, your ravenous desire for a slice of pizza post late-night-rendezvous might make you disagree, but listen up—let’s break it down.
Hunger and food cravings originate in different regions of the brain. While hunger operates out of the hypothalamus, that little area next to the pituitary gland, food cravings operate more centrally in regions like the nucleus accumbens. Both hunger and food cravings, however, are associated with the brain’s reward system, which basically pumps out feel-good chemicals such as dopamine when you do things that keep you alive, like eating.
Under the umbrella of hunger, there exists a distinction: homeostatic hunger and hedonic hunger.
Homeostatic hunger has been acknowledged for its evolutionary importance, as this type of hunger is signaled by the brain to indicate the body’s need for food as fuel. Hedonic hunger, a term coined in 2007, conceptualizes the desire for food that arises solely out of pleasure. Hedonic hunger seeks highly palatable foods that are rich in fat and high in sugar (think: carbs). Food cravings are often for these types of food, but the important distinction is that cravings are specific, while hedonic hunger is for palatable foods in general. How do cravings occur then? Here are two theories.
The elaborated intrusion theory considers the idea that, well, humans really love food. We love the taste of it, we love the smell of it it, (some of us) love cooking it, and so, naturally, we love to think about it. Food. Food. Food. All-day long. You’re probably thinking about food right now. Go on, think about it as you read this and see if a certain food crosses your mind. The elaborated intrusion theory explains that, once we are no longer distracted by a task, we experience invasive, conscious realizations of hunger. Once we recognize we are hungry it becomes pretty much the only thought on our minds. As we dwell on the thought of food we begin to imagine the sexiness of it: conjuring up images, tastes, and smells. The longer we think, the theory suggests, the stronger the desire to eat and the more specific our craving becomes. So, while you may at first have a general inkling for bread, upon further contemplation you might feel a gripping desire for a slice of warm toasted olive ciabatta from the Bread Alone stand at the Union Square Greenmarket, just absolutely dripping in butter with those crispy edges and… you get the point.
The other theory about why people experience food cravings is rooted in psychological thinking. Given that food is a primal activity, the impact of eating is highly emotional. Not emotional in the sense that you'd cry after a delicious meal, but instead more in the sense of how you might develop an attachment to donuts during stressful times, given the sugary surge of dopamine. These emotional connections with certain foods are thought to have developed during childhood and other sensitive periods in our lives. When I was younger and would get sick my mom would cook me congee, a rice porridge. Now, it is the food I crave when I’m feeling ill or seeking comfort. This theory, based on emotional conditioning, explains the variability in food cravings across the world, as people of different cultures often crave foods that are most familiar to their upbringing. For research purposes I consulted some friends: Sam, who hails from London, craves “tea and biscuits” in his times of need whereas Joanna, who grew up eating Chinese food, typically goes for a “sizzling broth.” As you can see, there is probably some truth in both these theories.
A common misconception about cravings, however, is that our bodies crave food based on nutritional deficiencies. For instance, someone lacking iron in their diet might have recurring visions of a juicy steak. The nutrition theory - though nice to believe that our bodies are this highly evolved - lacks scientific evidence. Bummer. Just because your craving for a huge ice cream sundae or a steaming basket of dumplings might not be what your body needs nutritionally, that shouldn't stop you from going out and getting some. Allowing yourself to enjoy a craving in moderation while still maintaining a balanced diet can prevent you from binging in the future and makes healthy eating feel more approachable overall. In the name of science: take a bite and indulge in the foods that matter to you.