Why do we eat sugary foods when we’re sad?

In the movie Austin Powers, the character who goes by the name Fat Bastard explains that he eats because he's unhappy but he's unhappy because he eats. We can sometimes find ourselves eating foods like chips, ice cream or chocolate after something happens that makes us feel sad, upset or nervous. Just think about the last time you were in a restaurant: have you ever finished your meal and found yourself to be full, only to later to order a dessert when the server asks if you'd like anything else? There's a couple reasons why we're like this, but it usually has to do with either an emotional connection between food and our feelings, or that the chemicals contained in sugary snacks create a chemical reaction in our brains. 

Emotional connection

According to a study from the University of Buffalo, the reason we're attracted to comfort foods when we're sad is because of the memories it recalls of the person who made it.

Comfort foods are often the foods that our caregivers gave us when we were children. As long we have positive association with the person who made that food then there’s a good chance that you will be drawn to that food during times of rejection or isolation.
— Shira Gabriel, University of Buffalo psychologist

Comfort food has been found to reduce feelings of rejection and isolation and it serves as a social function. It's appealing for us when we're feeling lonely and explains why we might be eating this sort of food, even if we're not actually hungry.

Though the foods that people choose to eat can vary greatly, all have roots in what they ate as a child. In a previous study participants had all been given a standard food to use as comfort food, but only those who had an emotional connection with the food found it comforting to them.

Chemical reactions 

There might be another reason why we eat sugary foods when we're sad or upset — chocolate contains tryptophan, a chemical that is used by the brain to make serotonin, a neurotransmitter that can make you feel happy. According to BBC Focus Magazine, it also contains phenylethylalanine, a chemical that makes us feel attracted and excited about someone or something and theobromine, a chemical that gives us a slight "high" after eating some chocolate.

Throughout evolution we had to eat as much as we could when we found food, because we could not be sure when we would be able to find more. This habit still is present in our modern day, and we can occasionally find ourselves eating fatty, salty and sugary foods after we're full because we're not sure when we'll see them again, even though we might have more right at home.

Our bodies have cues to tell us to stop eating, explains Gary Wenk, author of Your Brain on Food. Food travels through our stomach into the upper small intestine, and once it reaches here, our brain sends us a signal to stop eating. Ideally this would hint at someone to stop eating, but diners sometimes ignore these signs.

When something we're eating tastes good to us, we generally eat it until it is gone instead of until we're full. To help prevent this, try eating when you're getting slightly hungry to prevent overeating and to stop eating once you're comfortably full.