Scientists may have finally solved a key weight loss mystery

Scientists may have finally solved a key weight loss mystery

We may now be a step closer to explaining the ‘yo-yo’ effect seen in weight loss.

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Published: November 18, 2024 at 5:02 pm

A universal truth of weight loss: even if you manage to shed some body fat, you’ll probably find it’s harder to keep it all from coming back. 

Why does this happen? A new study may have the answer: fat tissue retains a 'memory' of sorts after the cells become obese.

“This is a piece of the puzzle in potentially explaining how adipose tissue [body fat] changes occur during weight change,” Dr Ferdinand von Meyenn, assistant prof at ETH Zürich’s Department of Health Sciences and Technology, explained to BBC Science Focus.

Von Meyenn and his team found transcriptional changes – changes to the way our cells copy and control genetic material – in the cells of humans they studied. They compared the sequences of cells within the fat tissue of individuals who were and were not living with obesity before and after a 25 per cent reduction in their BMIs. 

“The genes [we looked at] were so deregulated during obesity, that they did not return back to their normal state, even at transcription level,” says von Meyenn. “The body really fights against [weight loss] and wants to return back to its original weight. The adipose tissue is programmed to want to regain that weight.”

This is probably not the news people on weight loss journeys want to hear. However, von Meyenn shared hopes that this new research will help destigmatise weight fluctuations.

“People who cannot maintain their body weight are not just ‘weak’ people. There really is an underlying molecular mechanism driving gaining the weight back,” he said.

Von Meyenn also expressed that the best strategies to help with global obesity trends are preventative. “Intervention early on is really key because once you have gained weight, it will be much harder to lose it again," he said. "So, at a societal level, enforcing healthier living measures is quite important.” 

About our expert

Dr von Meyenn works in ETH Zürich’s Laboratory of Nutrition and Metabolic Epigenetics, which investigates obesity and metabolic diseases.

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