Does this explain your sugar cravings? Study finds junk food physically rewires brain to subconsciously crave more

Eating food high in sugar and fat rewires the brain to subconsciously prefer junk, a study suggests.

The study by scientists in Germany and the US measured the brain activity of a group given a dessert high in fat and sugar each day for two months.

They found that the brain reactions of those given the pudding significantly increased after eight weeks – particularly activating the region responsible for motivation and reward and releasing dopamine.

The study’s authors concluded the brains learn to subconsciously prefer and crave these fatty and sugary foods – even when people stop eating them.

The research team, from the Max Planck Institute for Metabolism Research in Cologne, western Germany, and Yale University, tested their hypothesis by selecting two groups of volunteers.

One group was given a small pudding containing high levels of fat and sugar each day for eight weeks, to be eaten alongside their normal diet.

Another control group received a daily dessert which contained the exact same amount of calories – but less fat.

The brain activity of the volunteers in both groups was measured before and during the eight-week experiment.

The study team, led by Dr Marc Tittgemeyer, observed that the brain’s responses to sugar and fat-rich foods in the group that ate the daily high-fat and sugar dessert were greatly increased after the eight weeks.

This increased activity especially activated the ‘dopaminergic’ system – which releases the feel-good hormone dopamine in the region of the brain responsible for motivation and reward.

Dopamine releases give us a sense of pleasure and the motivation to do something when we’re feeling pleasure.

Every time we do something we enjoy – such as having sex, eating food we like or exercising – small amounts of dopamine are released into our brains.

However, vices such as drinking alcohol and taking recreational drugs can also cause the release of dopamine.

Dr Tittgemeyer explained that our brains learn to prefer foods high in sugar and fat due to the cerebral activity – such as dopamine release – we experience when we eat them.

He said: ‘Our measurements of brain activity showed that the brain rewires itself through the consumption of chips and co.

‘It subconsciously learns to prefer rewarding food.

‘Through these changes in the brain, we will unconsciously always prefer the foods that contain a lot of fat and sugar.’

Sharmili Edwin Thanarajah, another lead author of the study, added: ‘Our tendency to eat high-fat and high-sugar foods – the so-called Western diet – could be innate or develop as a result of being overweight.

‘But we think that the brain learns this preference.’

During the study, the volunteers who gorged on the daily high-fat and sugar dessert didn’t gain more weight than those in the control group.

Their blood values, including blood sugar and cholesterol levels, didn’t change either.

But Dr Tittgemeyer and his team believe the preference for sugary and fatty foods in the test group will continue after the end of the study, as the brain neglects to forget it enjoys unhealthy foods.

‘New connections are made in the brain, and they don’t dissolve so quickly,’ Dr Tittgemeyers says.

‘After all, the whole point of learning is that once you learn something, you don’t forget it so quickly.’