A remote peninsula populated by tribes largely untouched by modern civilisation may seem an unlikely place for the latest diet fad to emerge.

Yet experts believe the traditional eating habits of rural Papua New Guinea may hold vital clues to tackling the Western world’s epidemic of chronic illnesses such as heart disease, obesity and diabetes.

More than 9.1 million people in England are expected to be living with major illness by 2040, according to the Health Foundation – about 2.5 million more than in 2019.

Yet in some parts of Papua New Guinea – one of the poorest countries in the world – obesity, type 2 diabetes and cardiovascular disease are strikingly uncommon, a phenomenon that has puzzled scientists for decades.

Now researchers believe they may have found the explanation for such remarkably low rates of chronic illness and longer healthy lifespans: their traditional diet.

And following impressive trial results, they’ve gone so far as to develop their own easy-to-follow eating plan, inspired by the diets of rural Papua New Guinean villagers, that anyone can try.

Called the NiMe diet – short for Non-Industrialised Microbiome Restore – the plan is notably simple. There is no calorie counting, expensive supplements or complicated fasting schedule.

Instead, meals revolve around beans and vegetables, with only small amounts of meat or fish and virtually no processed food, dairy or wheat.

Studying the microbiomes of Papua New Guineans inspired Professor Walter and his former PhD student, dietitian Dr Anissa Armet, to create a version of the diet using foods easily available in Western countries

Researchers believe they may have found the explanation for such remarkably low rates of chronic illness and longer healthy lifespans among Papua New Guineans: their traditional diet

The aim is not simply to nourish the body but to restore the gut microbiome – the trillions of bacteria increasingly linked to everything from immunity to metabolism and mental health.

In a trial carried out in Canada, volunteers who followed the fibre-rich, plant-heavy regime for just three weeks saw improvements in several markers linked to chronic disease. The results showed that participants recorded lower ‘bad’ cholesterol, improved blood sugar control, reduced inflammation and even lost weight – despite eating around 2,500 calories a day.

Lead researcher Professor Jens Walter believes that, long-term, the diet could even help reduce the risk of diseases such as bowel cancer, which has more than doubled in younger adults since the 1990s.

‘Our modern diet has a lot of health benefits, in terms of reducing malnutrition as well as preventing food-related infection and illness,’ says Professor Walter, who lectures in ecology, food and the microbiome at University College Cork. ‘But these advantages have come with collateral damage. We’ve traded infections and malnutrition for chronic disease.’

Having studied the microbiome for more than 25 years, he believes this is closely linked to the way our diets have changed over the past century.

As industrial food production took off, diets based around fresh, simple foods were increasingly replaced by heavily processed products designed to last longer. White bread, packaged snacks and ready meals became staples.

But while diets changed rapidly, the human body – and those all-important gut microbes – did not have time to adapt.

‘Our diet and gut microbiome has changed many times throughout human evolution,’ says Professor Walter. ‘But the most drastic change was caused by industrialisation – and it occurred so fast, our biology wasn’t able to catch up with it.’

In a trial carried out in Canada, volunteers who followed the fibre-rich, plant-heavy regime for just three weeks saw improvements in several markers linked to chronic disease (pictured, green pea curry from Dr Armet’s Instagram)

The researchers designed meals around ingredients including sweet potato, whole grains such as quinoa and barley, and plant proteins such as lentils, peas and tofu (pictured, sweet potato hash from Dr Armet’s Instagram)

The traditional diet eaten in rural Papua New Guinea is rich in fibrous foods such as leafy greens, fruit and vegetables (pictured, coleslaw from Dr Armet’s Instagram)

He believes this mismatch has helped drive soaring rates of obesity, type 2 diabetes and heart disease. Some illnesses – including colorectal cancer – have also been linked to low fibre intake (studies suggest about 95 per cent of Britons fail to eat enough).

The traditional diet eaten in rural Papua New Guinea looks very different. It’s rich in fibrous foods such as leafy greens, fruit and vegetables, contains very little meat or dairy and includes no ultra-processed food.

According to Professor Walter, stool samples from these communities show low levels of inflammation and a highly diverse gut microbiome – both linked to better long-term health.

Studying the microbiomes of Papua New Guineans inspired Professor Walter and his former PhD student, dietitian Dr Anissa Armet, to create a version of the diet using foods easily available in Western countries.

Rather than relying on Papua New Guinean staples such as sago (a starch from palms), cassava (a starchy root vegetable) and breadfruit (a tropical fruit, which can be prepared like potato), they designed meals around ingredients including sweet potato, whole grains such as quinoa and barley, and plant proteins such as lentils, peas and tofu.

Small portions of fish, poultry or eggs are allowed daily, while lean red meat is limited to once a week.

Fibre is central to the plan. While UK guidelines recommend 30g a day, the NiMe diet contains around 45g.

And, importantly, it is not just about what foods are eaten, but how they are prepared.

Professor Jens Walter developed the NiMe diet with a former PhD student

NiMe recipes require carbohydrates such as whole grains and sweet potatoes to be cooled after cooking to change the starches in them, creating what’s known as resistant starch – a form that’s harder for the body to break down.

Instead of being rapidly absorbed, it passes further into the gut where it helps feed beneficial bacteria.

To test the diet, Professor Walter’s team carried out a three-week trial involving 30 volunteers, mostly healthy men and women aged about 27. All meals and snacks were prepared by researchers.

The team then analysed blood and stool samples.

While the volunteers’ microbiomes changed relatively little, many other health markers showed clear improvement. Despite consuming the same calories as before – about 2,500 a day for men and 2,000 for women – participants lost weight, averaging 2.5 lb in men and 2.2 lb in women.

Participants also saw their LDL, or ‘bad’ cholesterol, fall by 17 per cent.

Levels of C-reactive protein – a marker linked to inflammation and heart disease – fell by 14 per cent. And researchers also noted improvements in blood sugar levels and increases in compounds linked to protection against type 2 diabetes.

‘The high-fibre aspect of the diet showed benefits for gut health as well – reducing inflammation and rebuilding the gut wall, as well as increasing levels of short-chain fatty acids, which improve digestion and immune function,’ says Professor Walter.

Participants even saw reductions in markers linked to cancer risk, particularly bowel cancer. ‘There’s good evidence that colorectal cancer is linked to high consumption of animal fat and low fibre intake,’ he adds. ‘To prove that the NiMe diet reduces the risk of colon cancer, we’d need a 2,000-person study lasting 20 years. But we could already see markers linked to the disease falling after just three weeks.’

The scale of the changes surprised even the researchers, who are now applying for funding to study the long-term effects of the diet.

In the meantime, sample NiMe recipes are freely available online. ‘We wanted to make it available to anyone,’ says Professor Walter. Yet some experts are more cautious.

‘Any diet high in fruits, vegetables and plant-based foods is likely to produce positive health effects,’ says Dr Gunter Kuhnle, professor of food and nutritional sciences at the University of Reading. ‘And people in studies like these often lose weight simply because they pay more attention to what they eat.’

He also warns that scientists still do not fully understand what an ideal gut microbiome looks like. ‘There are many more ways to improve the gut microbiome than this specialised diet – eating probiotics is an easy one,’ he adds.

Dr Ruairi Robertson, a gut microbiome scientist at Queen Mary University of London, believes the NiMe diet does offer something distinctive, however. ‘What stands out is the much higher proportion of fibre, which has been neglected in the UK for years,’ he says.

Professor Walter says he’s personally experienced the benefits of changing his diet.

‘I used to be borderline overweight,’ he says. ‘I was very sporty when younger, but after an injury I stopped exercising and didn’t change the way I ate. It was lots of fatty and sugary junk food. My cholesterol and blood sugar skyrocketed.’

Despite not following the NiMe diet overly strictly, he says he’s ‘lost all the weight now’. ‘My cholesterol has gone back down and I feel much healthier. I feel better in my 40s than I ever have before.’

Want to eat like a Papua New Guinean? Try this microbiome-friendly salmon dinner recipe

Ingredients:

For the salmon:

• 95g fresh salmon fillets
• 1 tbsp maple syrup
• 1 tbsp soy sauce
• ½ tsp minced garlic
• ¼ tsp black pepper 

For the vegetables:

• 150g brussels sprouts, cut in half
• 100g sweet potato, peeled and chopped 
• 2 tsp olive oil  
• 1 tsp minced garlic
• ½ tsp salt
• ¼ tsp black pepper 

Directions:

Preheat oven to 400F / 200C / gas mark 6.

Add all of the vegetables to a casserole dish lined with parchment paper and stir well.

Place in the oven and bake for 20 minutes.

Take out, toss and bake for an additional 15-20 minutes until the vegetables are browned and softened.

Meanwhile, combine the maple syrup, soy sauce, garlic, and pepper in a small dish for the marinade, and score the surface of the salmon with a knife, cutting ¼in (0.5cm) deep.

Place the salmon fillets in a shallow glass baking dish lined with parchment paper and coat them with the marinade.

Place the dish back in the oven and bake the salmon uncovered until the internal temperature reads 70C (158F) – it should take about 20 minutes.

Serve with brown rice.