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This study expands on existing research, Kullman says, showing the communication between our guts and brains, and how the axis is different for people who are obese. Specifically, people who are obese are more likely to choose bigger portions of food when thinking about pleasure.
Participants in Kullmann’s study were told to return to their normal diet after the five days, but one week later, further tests showed that the memory and cognitive parts of their brains were still less responsive than before beginning their higher calorie diet.
So is it OK to indulge at Christmas?
It is well established that prolonged periods of eating – especially foods high in sugar and saturated fats – aren’t good for the brain. While there are fewer studies looking at the impacts of a one-off feast on our bodies, existing evidence suggests it’s not detrimental to our brains.
“Our study shows that one-off indulgence is not as damaging as you might expect, so enjoy your Christmas dinner,” says Hengist.
However, he adds, any more than this can start to put strain on the body. Even five days might be enough to have longer-lasting effects on the brain, according to Kullman’s research.
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