We can’t stop thinking about them; as much as we try to avoid them, the thoughts keep lingering in the brain until we satisfy our food cravings. The unshakeable desire for specific foods like chocolate or potato chips is not actual physiological hunger, but a psychological starvation that needs to be fed. So, what triggers unleash our stomach’s ravenous hunger for certain foods?

In Sci Show's latest video, "What Causes Food Cravings?" host Michael Aranda explains food cravings are different from hunger. When our stomach is empty and our blood levels start to drop, the body starts to secrete ghrelin, otherwise known as “the hunger hormone.” Ghrelin tells the hypothalamus in our brains we need to eat, triggering a chain reaction that revs up our appetite and the digestive system ready to receive food. Once we devour enough food to stretch our stomach a bit, ghrelin turns off and makes us feel satiated for awhile.

Now, when we crave a particular food, this may signal we need more of a specific nutrient. For example, if we're very low on salt, we might crave potato chips or pretzels. But, if we need something more specific, like magnesium, there's no evidence we'll start craving chocolate even though chocolate does have magnesium in it. Often, cravings are more about a psychological hunger than a physiological one, and can be induced by emotions like stress and anxiety.

If we eat a butter-frosted cupcake or a bag of salty French fries, it releases an opioid typhoon that lights up the brain's pleasure center and makes us feel better — temporarily. It's no surprise cravings are also tied to the brain's memory center, which explains why we might crave a food that isn't full of fat or sugar. Our brain may tie our food craving to a happy memory, or a feeling of reward. Therefore, thinking about a memory associated with a food can make us crave it.

Restrictive or boring diets can also trigger food cravings. In studies where participants could drink only meal replacement shakes, they were left jonesing for more craved foods than usual, specifically for solid foods. Their diet contained all the calories and nutrients that participants' bodies needed. This suggests the extra cravings weren't induced by a deficiency in nutrients.

Similarly, a pregnant woman's cravings for pickles or ice cream is theorized to be linked to hormones. However, there isn't much evidence for this connection, but instead, these cravings probably have to do more with mood.

So, the next time we get a sweet tooth, it’s most likely linked to a memory, and not actual hunger pangs.