Lead author Dr Eirini Dimidi, reader in nutritional sciences at KCL, said: “Chronic constipation can have a huge impact on someone’s day-to-day life.

“For the first time, we’ve provided direction on what dietary approaches could genuinely help, and which diet advice lacks evidence. 

“Improving this condition through dietary changes would enable individuals to manage their symptoms independently, potentially enhancing their quality of life,” the researchers stated.

The panel offered 59 recommendations, suggesting that patients might benefit from consuming two to three kiwifruits daily for four weeks to address constipation issues.

Experts recommend eating kiwifruits without the skin, as the skin adds extra fiber, which may increase potential side effects. These fruits are available at supermarkets like Tesco, priced as low as 20p (£1.19 for a six-pack).

Patients might also be advised to consume six to eight slices of rye bread daily for a minimum of three weeks, although they acknowledged that this “might not be practical or feasible for some individuals.”

Dr Dimidi added: “Eating a high fibre diet offers many benefits to overall health and has been a go-to recommendation for constipation. 

“However, our guidelines found that there simply isn’t enough evidence to suggest it actually works in constipation specifically.

“Instead, our research reveals some new dietary strategies that could indeed help patients. At the same time, we urgently need more high-quality trials to strengthen the evidence on what works and what doesn’t.”

The  findings were published in two international journals, the Journal of Human Nutrition & Dietetics and Neurogastroenterology & Motility.

Dr Yvonne Jeanes, head of research and impact at the British Dietetic Association, said: “These guidelines are an excellent resource for dietitians and healthcare professionals more broadly, they support a more diet focused and evidenced-based approach to the management of chronic constipation.”