Losing Weight By Intermittent Fasting Can Alter Brain Activity, Study Suggests

Losing weight by intermittent fasting can dramatically alter brain activity for appetite and addiction, a new research has revealed. According to the New York Post, researchers at the Health Management Institute in Beijing found that this trendy weight loss method which has been touted by celebrities including Jennifer Aniston and Gwyneth Paltrow, can lead to significantly changed gut bacteria and brain activity, with both positive and negative effects. Notably, the intermittent energy restriction (IER) diet involves days of relative fasting alternated with days of eating normally.

The study, published in Frontiers in Cellular and Infection Microbiology, revealed that people who took part in the research lost an average of 7.5 kilograms in two months. After IER, researchers found the participants were seen to have decreases in the activity of brain regions implicated in the regulation of appetite and addiction. There was also an increase in the abundance of certain gut bacteria that can help with attention, motor, inhibition, emotion and learning, the study revealed. 

"Here we show that an IER diet changes the human brain-gut-microbiome axis," said the HMI's Dr Qiang Zeng, as per the Post. "The observed changes in the gut microbiome and in the activity in addition-related brain regions during and after weight loss are highly dynamic and coupled over time," he added. 

To get the result, the researchers studied stool samples from 25 Chinese men and women on an IER diet. First, participants underwent a 32-day "high-controlled fasting phase," where they ate dietician-designed meals personalized to their needs. Following this, the participants spent 30 days in what's called a "low-controlled fasting phase", in which they were allowed to make more of their own choices. 

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Participants who adhered perfectly to this diet received 500 calories per day for women and 600 calories per day for men. By the end, their body had decreased by an average of 7.5 kg, with reductions in body fat and waist circumference, the study revealed. Other noticeable effects were a decrease in blood pressure and cholesterol as well as changes to brain activity and the gut microbiome, researchers said. 

However, the study also suggests that IER helps to reduce obesity-related issues such as hypertension, hyperlipidemia and liver dysfunction. But there were also changes to the gut bacteria that may have negative side effects on executive function, including our will to lose weight.

"A healthy, balanced gut microbiome is critical for energy homeostasis and maintaining normal weight," said Dr Yongli Li, also from the Department of Health Management. "In contrast, an abnormal gut microbiome can change our eating behaviour by affecting certain brain areas involved in addiction," Dr Li added.