Surgeon explains the five ways fibre triggers natural weight loss

While fibre is often hailed for keeping us regular, its role in weight management is far more sophisticated.

Dr Karan Rajan, a prominent UK surgeon, recently explained that while fibre isn't a magical weight-loss pill, it acts as a powerful internal regulator. In an Instagram update on Thursday, he detailed how fibre helps the body work more efficiently.

Gastric distension

Fibre provides physical bulk. Dr Rajan explains: “Fibre physically stretches your stomach. This triggers mechanoreceptors to send a signal to your brain stem via your vagus nerve so you feel satisfied on fewer calories.”

Slowed gastric emptying

Soluble fibre turns into a gel, which acts like a biological speed bump. He states: “Food exits more slowly, so you stay fuller for longer between meals and do less snacking.”

Gut hormone release

Fibre naturally triggers the same satiety signals as popular weight-loss drugs. Dr Rajan notes: “The presence of fibre in your intestines stimulates L-cells to release GLP-1 and PYY, the same hormones that Ozempic mimics.”

Microbiome fermentation and absorption

In the colon, bacteria ferment fibre to produce fatty acids that lower hunger. Furthermore, high-fibre meals can lower calorie intake because "some nutrients bind to the fibre and pass through undigested."

However, the surgeon warns that "fibre can't override thermodynamics." It simply makes a calorie deficit easier to maintain by reducing hunger.

While supplements are a useful tool, he urges people to prioritise whole foods for their complex nutrients, noting: “Do not use supplements as an excuse to never eat fibre-rich foods.”

Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.