What is it about burgers and cakes that we crave?

And what is happening in our brains when we choose what to eat?

If you hopped into an MRI machine and were offered a delicious chocolate milkshake, you would see your brain's reward system light up like a funfair.

Right above your eyes is your orbitofrontal cortex, a part of the brain which is especially developed in humans and primates.

Here, bundles of neurons respond to different sensations and nutrients - taste, smell, how smooth and rich the milkshake feels - and the more your neurons light up, the more delicious the food seems.

Two things which particularly delight these reward neurons are fat and sugar.

Combinations of fat and sugar can be even more delightful, such as in that delicious milkshake, or cakes, or doughnuts.

But your neurons don't just respond to these sensations, they also activate when you're planning what to eat in a contest with each other to get you to choose them.

"Pick me." says silky smooth mouth feel.

"No! Me!" shouts sugary sweetness.

"You never pick me." quietly mumbles the smell of broccoli.

And once you have chosen, the same neurons track your progress, and as you eat, they get less and less active as you approach fullness.

But we're not entirely at the mercy of the demands of our orbitofrontal cortex.

Having information about the food can make a big difference.

Hop back into that MRI machine and slurp down some soup.

There are two types - one is labelled "rich and delicious flavor", and the other is labelled "boiled vegetable water."

Your neurons light up at the taste of "rich and delicious", and less for "boiled vegetable water."

But wait a minute, you've been tricked! Those were both the same soup.

The only difference was the name and that was enough to completely change your experience of it.

This experiment was also done with wine - telling people that the wine cost more made their neuron activity increase and the wine tasted better.

Another part of the brain involved in choosing food is the amygdala.

The amygdala also has a role to play when you choose where to go out with another person.

If you've seen what they prefer in the past, your amygdala will have developed so-called simulation neurons.

These predict the choice you think they will make which you can then factor into your own suggestions of what to eat together.

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

Scientific experiments give us clues about how our brains compute our choices of what to eat, but the way we experience these choices in our lives and in society is also complex.

Dr. Emily Contois, Assistant Professor of Media Studies, gives her take.

We choose the food we eat for a lot of different reasons:

What's available at the grocery store? What's convenient?

What's affordable? What do we have good memories about?

What taste is good to us? What do we think is healthy?

What is our current health status?

What defines our ideas about who we are?

So when we think about food in the digital age, one of the biggest things that has changed the way people eat and the kinds of foods that they are seeking out are social media platforms.

Instagram, and the desire for people to be able to take beautiful food photos, has transformed the idea that you are what you eat into you are what you post.

So we seek a lot of different things from the food that we eat.

We can seek comfort, we can seek a connection to history, to our families, to our heritage.

But we can also seek in it a sense of control.

When we live in moments that are full of economic, political and social strife, sometimes we seek in food that sense of security and safety.

So in those moments, we sometimes see people get really interested in ideas about naturalness, health and purity, as a way to protect ourselves from contexts outside of our control.

So food also tells stories about who we are. The full 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 about our social class, the region where we live, even whether we live in an urban or a rural area.

What we eat tells these contradictory, complex stories about who we are.

In the future, we can use our knowledge of what is happening in our brains to design foods that are low in calories and are still attractive, but healthy.

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

We can be aware of times that we tend to make poor choices, like when we choose a food because of some label which appeals to us, rather than because of its taste.

So in the end, we are at least not fully at the mercy of our reward neurons.

We can use our understanding to help design healthy foods and make healthy choices.