Sweets change our brain: Why we can't keep our hands off chocolate
Foods with a high fat and sugar content change our brain: If we regularly eat even small amounts of them, the brain learns to consume precisely these foods in the future.
FAB RESEARCH COMMENT:
Previous research has already shown that ultra-processed foods such as chocolate, cakes, or ice cream that are high in both sugar and fat, are 'hyper-palatable' and therefore override normal satiety mechanisms, leading to over-consumption.(Much of that research has of course been done by the food industry, seeking to make their products even more 'hyper-palatable' - i.e. difficult to resist even when you are full already - as it is in their interests for people to eat more, so that they can sell more...)
This new study measured brain activity in volunteers who were randomly allocated to eat a daily snack for 8 weeks in addition to their usual diet. These were matched for calorie content, but while one was high in BOTH fat and sugar, the other was high in sugar only.
- Consumers of the high-fat, high-sugar snack showed significant increases in activity in 'reward' areas of the brain, which was interpreted as a 'rewiring' of their food preferences - i.e. an unconscious learning effect.
But there really is no reason to favour any single explanation, and these factors are all interlinked to some extent in any case.
An abundance of good evidence indicates that consistent high exposure to high-sugar, high-fat, ultra-processed 'convenience' foods is a major contributor to the current worldwide epidemic of overweight, obesity and related eating disorders.
Randomised controlled trials have already shown that consuming ultra-processed vs whole or minimally processed foods for just one to two weeks leads to:
- overeating without being aware of it, and significant weight gain
- increased cravings for 'junk foods', even when feeling full; and memory problems
Other evidence shows that mothers' diets during pregnancy can have a lasting influence on the taste and food preferences of her unborn child - as well as its metabolism and future health risks - via 'nutritional programming' effects - which involve a form of 'learning' from environmental experience/exposure, but become 'hardwired' or 'innate' because they permanently alter gene expression.
- these include the future ability of that child to resist high-fat, high-sugar foods - IF exposed to them
Importantly, this study showed that it was foods high in BOTH sugar AND fat that triggered the 'rewiring' of reward responses in the brain, not the calorie-matched control foods that were high in sugar only.
As usual, however, the sub-heading in this news article misleadingly refers to them only as 'high-fat' snacks.... not high-fat AND high-sugar - keeping up the myth that 'high-fat' foods and diets are the problem behind overeating - rather than the combination of high fat with high sugar content (or with high salt, which also contributes to the 'hyperpalatibility' of the unhealthiest forms of ultra-processed food - i.e. the HFSS category).
For details of the underlying research, see:
22/03/2023 - Medical Xpress
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Chocolate bars, crisps and fries—why can't we just ignore them in the supermarket? Researchers at the Max Planck Institute for Metabolism Research in Cologne, in collaboration with Yale University, have now shown that foods with a high fat and sugar content change our brain: If we regularly eat even small amounts of them, the brain learns to consume precisely these foods in the future.
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Chocolate bars, crisps and fries—why can't we just ignore them in the supermarket? Researchers at the Max Planck Institute for Metabolism Research in Cologne, in collaboration with Yale University, have now shown that foods with a high fat and sugar content change our brain: If we regularly eat even small amounts of them, the brain learns to consume precisely these foods in the future.
The paper is published in the journal Cell Metabolism.
Why do we like unhealthy and fattening foods so much? How does this preference develop in the brain?
"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," explains Sharmili Edwin Thanarajah, lead author of the study.
"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," explains Sharmili Edwin Thanarajah, lead author of the study.
To test this hypothesis, the researchers gave one group of volunteers a small pudding containing a lot of fat and sugar per day for eight weeks in addition to their normal diet.
The other group received a pudding that contained the same number of calories but less fat. The volunteer's brain activity was measured before and during the eight weeks.
The other group received a pudding that contained the same number of calories but less fat. The volunteer's brain activity was measured before and during the eight weeks.
Our brain unconsciously learns to prefer high-fat snacks
The brain's response to high-fat and high-sugar foods was greatly increased in the group that ate the high-sugar and high-fat pudding after eight weeks. This particularly activated the dopaminergic system, the region in the brain responsible for motivation and reward.
"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," explains Marc Tittgemeyer, who led the study.
"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," explains Marc Tittgemeyer, who led the study.
During the study period, the test persons did not gain more weight than the test persons in the control group and their blood values, such as blood sugar or cholesterol, did not change either.
However, the researchers assume that the preference for sugary foods will continue after the end of the study. "New connections are made in the brain, and they don't dissolve so quickly. After all, the whole point of learning is that once you learn something, you don't forget it so quickly," explains Marc Tittgemeyer.
However, the researchers assume that the preference for sugary foods will continue after the end of the study. "New connections are made in the brain, and they don't dissolve so quickly. After all, the whole point of learning is that once you learn something, you don't forget it so quickly," explains Marc Tittgemeyer.
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