How science explains why it’s so hard to resist sweet and fatty foods

Why is it so much easier to choose to eat a donut over a serving of steamed broccoli?

There’s no doubt that some foods arouse our desire more than others—especially those high in sugar and fat.

But why are they so irresistible?

Scientific experiments offer us some clues about what happens in our brains when we choose to eat certain foods.

According to neuroscientist Fabian Grabenhorst, if you were to step into an MRI machine and be offered a chocolate milkshake, you could see your brain’s reward system light up like an amusement park.

Just above the eyes is located the orbitofrontal cortex, a part of the brain that is especially developed in humans and primates.

In it, groups of neurons respond to different sensations and nutrients — taste, smell, how creamy and full-bodied the milkshake is — and the more their neurons light up, the more appetizing the food in question looks.

Two things that particularly cheer these reward neurons are fat and sugar.

And combinations of fat and sugar can be even more appealing, as in the case of a milkshake, a donut or a slice of pie.

But our neurons don’t just respond to these sensations, they are also activated when you’re planning what to eat — in a kind of competition with each other to be “chosen.”

And once you decide, the same neurons track your progress — as you eat, they become less and less active the closer you get to satiety.

But we are not entirely at the mercy of the demands of our orbitofrontal cortex. Having information about food can make a big difference.

Let’s go back to that MRI machine, and have some soup now. There are two types — one soup is labeled “rich and delicious” and the other is “boiled vegetable water.”

Your neurons light up more when you drink the “rich and delicious” soup, and less when you drink “boiled vegetable water.”

But there’s a catch: it’s the same soup. The only difference is the name, and that’s enough to completely change your experience, as studies show.

This experiment was also done with wine — telling people that a certain wine was more expensive increased neuron activity and made the wine taste better.

Another part of the brain involved in food choice is the amygdala—a structure located in the temporal (lateral) lobe, which processes our emotions.

It also plays a role when you decide where to go eat with someone else.

If you’ve seen in the past what this person prefers, your amygdala will have developed so-called simulation neurons — which allow you to predict the other person’s intentions and thus include them in your own suggestions of what to eat together.

Differences in our genes are also a factor in how susceptible we are to the siren song of our reward neurons — some people are naturally more responsive to the reward we feel from eating sugar and fat than others.

social aspect

Scientific experiments offer us clues about how our brains compute our choices about what to eat, but the way we deal with those choices in our lives and in society is also complex.

According to Emily Contois, assistant professor of Media Studies at the University of Tulsa in the US, several factors influence our choice of what to eat.

“What is available at the supermarket? What is convenient? What is affordable? What brings back good memories? What is delicious for us? What do we find healthy? What is our current health status? What defines our ideas about who we are?”, she lists for BBC Ideas.

And social networks, according to her, have gained an important role in this process.

“Instagram, and the desire for people to be able to take beautiful pictures of food, has turned the idea of ​​’you are what you eat’ into ‘you are what you post’,” he says.

Contois says we look for a number of different things from the food we eat — like comfort, connection to our family or our ancestral heritage, and even a sense of control.

“When we live in times full of economic, political and social conflicts, we sometimes look to food for that sense of security and protection. So, in those moments, we sometimes see people being very interested in ideas related to simplicity, health and purity, like a way to protect ourselves from contexts out of our control”, he explains.

In this way, food also speaks a little about who we are.

“(About) All the complexity of our identity. What we eat tells stories about our gender and our sexuality, our race and our ethnicity, our social class or our aspirations in relation to our social class, the region where we live, be it an area urban or rural. What we eat tells these complex and contradictory stories about who we are,” she says.

In the future, we can use our knowledge of what goes on in our brains to create attractive, low-calorie, healthy foods.

And we can help ourselves by understanding how our reward neurons plot to get what they want.

We can be aware of times when we tend to make the wrong choices, such as when we choose a certain food because of a label that we find attractive, rather than the content itself.

In the end, at least we’re not totally at the mercy of our reward neurons. We can use our understanding to help think about healthy foods and make healthy choices.