• John Tregoning, 47, tried 15 longevity hacks to see which ones were worth buying.
• The research scientist tried things like cold water swimming, gene sequencing, and blood analysis.
• Calorie restriction helped him lose weight, but he missed out on social activities.

As he entered his mid-40s, it finally hit John Tregoning that he was going to die one day.

Faced with his mortality, the vaccine immunologist based at Imperial College London, wondered if there was anything he could do to extend his lifespan (unlikely, he thought), or at least live healthier for longer.

He researched buzzy longevity treatments that he hoped would prevent conditions such as cancer, type 2 diabetes, and cardiovascular disease, which are leading causes of death.

He landed on trying: gene sequencing, whole-body blood analysis, an ECG, more exercise, cold water swimming, eating beetroot, eating less salt, Dry January and alcohol replacement, eating less red meat and more vegetables, brain training apps, sleeping more, a calorie restriction diet, eating more fiber, microbiome sequencing, and drinking more water. He documented his experience in his book "Live Forever? A Curious Scientist's Guide to Wellness, Ageing and Death."

Tregoning shared the three longevity hacks he thought were a waste of money.

Microbiome testing

The gut microbiome is the name given to the trillions of microbes that live in the colon lining. A gut microbiome with a diverse range of microbes is linked to better overall health — from the immune system to the brain.

Understanding how it works and impacts the body is a large area of research, however, there is still much scientists don't know, Tregoning said. But this hasn't stopped businesses from cashing in on the hype and selling products claiming to support gut health, he said.

Microbiome sampling, which involves sending your poop off to a lab to be tested, has become a readily available, albeit pricey, service. Most tests go for between $200 and $300.

Tregoning sampled his gut microbiome after making dietary changes on three separate occasions, to see if the results might help him make some gut-friendly changes to his diet.

The first sample was taken when he followed his typical diet, the second after he ate a curry and drank two bottles of beer, and the third after he ate 30 grams of fiber and three portions of fermented foods for a week, based on advice from a GI surgeon and researcher colleague.

The results showed that his microbiome had changed after the high-fiber week, but it had also unexpectedly become less diverse. A new type of bacteria had entered his microbiome, but the test couldn't tell him what that might mean for his health.

Tregoning said that the results were not useful because they weren't actionable, and only reflected the state of his gut at very specific times.

"Saying that this one bacteria in a sea of bacteria changes anything, we are nowhere close to that," Tregoning said. "It's a single snapshot. It's a bit like saying, 'How do you feel this second?' It changes all the time.

Calorie restriction diet

Calorie restriction, either through eating fewer calories or intermittent fasting, has been shown to extend the lifespan of mice. It can also help people who are overweight or obese reach a healthy weight, which can have beneficial knock-on effects for their health.

As part of his research, Tregoning tried a fast-mimicking diet for five days. He purchased a diet kit for £160 ($207), which came with packets of soup, nut bars, kale crackers, olives, and chicory root bars, which would provide him with 900 calories a day.

He lost more than six pounds in that week and kept it off for a month, but overall he didn't find the diet sustainable.

"It was effective in terms of I lost weight, but I was pretty listless and miserable for the whole week," Tregoning said. He wouldn't do it again mainly because it was too expensive and he largely had to stop socializing to follow it.

"It really pointed out to me how central food is in my life socially. In cooking with friends or cooking for family, having lunch at work with people, there's lots of social elements around food, which in that week I was missing out on," he said.

Social connection is crucial for longevity, and social isolation accelerates decline, healthspan, and lifespan, Trengoning said. This aligns with longevity research, which has found relationships to be as important for health as factors such as diet and exercise.

Gene sequencing

To assess his risk of developing certain health conditions, Tregoning did a genetic test.

He ordered a kit from 23andMe, which revealed that he doesn't have the gene variants for any of the 46 traits they measure or any of the 14 genes that make a person predisposed to a range of diseases, including breast cancer (BRCA2), Parkinson's disease, and age-related macular degeneration.

It also told him more trivial things like how likely he was to have back hair, and that his genes were likely 2% Neanderthal.

Overall, Tregoning did not find it a useful exercise. "It's fun, but it didn't really change anything in my understanding of what my personal risks are," he said. Our genes predicts likelihood rather than actual outcome, he said, and they are influenced by environmental factors and lifestyle.

"Environment is as important as our genes. The phrase I like is 'genes loads the gun, the environment pulls the trigger," he said.

• Jens Walter researches the gut health of people in industrialized and non-industrialized countries.
• His team's research suggests people in non-industrialized countries, like Papua New Guinea, have better gut health.
• He shared high-fiber recipes from the "non-industrialized microbiome restore," or NiMe, diet.

When Jens Walter first watched a documentary about Papua New Guinea as a child, he could never have predicted it would spark an obsession with the tropical Pacific island, which would not only shape his career but what he eats.

But 15 years later, his diet (heavy on plants, light on processed foods) is based on his research into what rural Papua New Guineans eat, which he believes could help improve the gut health of people in the West.

Walter, a professor of microbiology at University College Cork, Ireland, who specializes in gut health, told Business Insider that he first started studying Papua New Guinea in 2015, after he asked researchers in the country for poop samples the non-industrialized society. The majority of people (87%) in Papua New Guinea live in rural communities and rely on semi-subsistence farming, according to the International Fund for Agricultural Development.

By studying the poop, Walter wanted to understand whether industrialization affected the type and number of microbes in people's guts. Research suggests a diverse gut microbiome, the trillions of microorganisms that inhabit the digestive system, is linked to a range of health benefits, from better digestion to a stronger immune system.

He found that Papua New Guineans' gut microbiomes, — and, ergo, poop — were very different from those of people in industrialized, Western countries.

In the following decade, Walter started eating more vegetables, fewer processed foods, and less meat.

He now follows the "non-industrialized microbiome restore," or NiMe, diet which he and other researchers devised for a study published earlier this year in the journal Cell.

The NiMe diet is linked to a lower risk of chronic diseases

For three weeks, 30 healthy participants followed an "ancestral" diet comparable to what people eat in Papua New Guinea to see if their Western gut microbiomes could be restored to a pre-industrliazed state.

The study included meals that were plant-based, low in ultra-processed foods, low in dairy and wheat products, and contained, on average, double the amount of fiber the participants typically ate.

Staple foods in Papua New Guinea include sago, a starch extracted from the stems of palm plants, high-protein karuka nuts, sweet potatoes, cassava, breadfruit, and coconuts. However, the researchers created NiMe to combine the principles of a Papua New Guinean diet with foods accessible in the West.

The participants' gut microbiomes weren't restored to a fully pre-industrialized state, but the diet did improve their gut health. They had fewer signs of chronic disease risk found in the gut, including fewer microbes that cause inflammation, a lower pH, and better maintenance of the mucus lining, which can also cause inflammation if broken down. They also had lower cholesterol levels and increased insulin sensitivity.

The effects were similar to those seen in followers of plant-based and Mediterranean diets, the researchers wrote, suggesting that the abundance of whole foods and fiber in all three is linked to better overall health.

"I follow the diet with very few exceptions," he said. "But I sometimes cheat a little bit on the no dairy rule, because I like cheese a lot."

Here are four of the team's recipes.

Breakfast hash

For this breakfast hash recipe, season chopped Jerusalem artichokes, russet potatoes, and onion with salt, black pepper, and olive oil. Bake in the oven for 20 minutes.

Making this dish ahead of time and reheating it throughout the week could provide extra health benefits, the researchers said.

Reheating starchy foods, including potatoes, converts some of that starch into resistant fiber, which can reduce blood sugar spikes and has been linked to the prevention of type two diabetes and obesity, BI previously reported.

Salmon dinner

To make a gut-healthy salmon dinner, the researchers suggested serving a salmon fillet, baked with maple syrup, soy sauce, minced garlic, and black pepper, with brown rice.

They paired these with Brussels sprouts and sweet potatoes roasted in olive oil, salt, black pepper, and minced garlic.

Salmon is a great source of omega-3, which has been linked to a reduced risk of heart disease and better joint health.

Rice pudding

For breakfast or dessert, the researchers developed a rice pudding recipe. To make it, boil cooked brown rice, non-dairy milk (as the diet is low in dairy), cinnamon, vanilla, raisins, and honey until the mixture has thickened. Take off the stove and stir in some walnuts.

Different plant-based milks have varying nutritional benefits, but dietitians have previously told Business Insider that it's best to choose a milk alternative that is fortified with vitamins and minerals.

Quinoa tabbouleh

This quinoa tabbouleh is a great source of plant-based protein, the researchers said. Although plant-based sources of protein contain less of the macronutrient than meat, they contain much more fiber, which is a key part of the NiMe diet.

To make it, combine cooked quinoa and cannellini beans with chopped cucumber, red bell pepper, and green onions. Season with dried parsley, lemon juice, olive oil, salt, and black pepper.

Astronauts on the International Space Station often suffer from various immune system dysfunctions, including allergies and skin rashes, even though they go through rigorous screening and are probably among the healthiest people on (or at least near) Earth. “It’s hard to pinpoint the exact causes for a lot of these symptoms, but we believe microbiome disruptions that happen in their bodies and in their environment up there could be playing an important part”, says Rodolfo Salido Benitez, a bioengineering researcher at the University of California, San Diego who co-authored the largest study on the ISS microbiome to date.

After analyzing over 800 samples collected by astronauts in multiple modules of the United States Orbital Segment in the ISS, Benitez and his team concluded the microbial and chemical environment on the station closely resembled the one found at COVID-19 isolation wards during the height of the pandemic. And that may be less than ideal for keeping people healthy.

Swabbing the space decks

Monitoring microbial life on the ISS is an ongoing effort, and studies of this sort have been done before, although at a much smaller scale. “Previous studies used a low number of samples that could not identify all microbial and chemical factors present up there,” said Nina Zhao, a researcher at the UCSD and co-author of the study.

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• Valerie Taylor studies the link between our gut health and mental health.
• She said gut microbes, the brain, and central nervous system can influence one another via the "gut-brain axis."
• Her tips for caring for gut health include eating a nutritious diet that suits you best.

A professor of psychiatry shared three ways caring for our gut health could improve our mental health.

Valerie Taylor, who is based at the University of Calgary, studies the relationship between the gut microbiome — the trillions of microorganisms in the digestive system — and the brain.

The gut microbiome is a rapidly growing area of research, with more than 40 times as much funding for related research in the US in 2016 as there was in 2007.

Research suggests that gut microbes, the brain, and the central nervous system can influence each other via what is known as the "gut-brain axis," including by regulating the production of certain chemicals.

For example, when people get stressed, their bodies release more of the "stress hormone" cortisol, which can make the gastrointestinal system digest food faster, leading to diarrhea or an upset stomach, Taylor said.

Although the research is promising, Taylor doesn't think that addressing gut health can "cure" mental health conditions such as depression and anxiety.

But a greater understanding of the gut-brain axis could encourage people to make lifestyle changes that could improve their gut and mental health, Taylor said. Experts are increasingly questioning the idea that depression, for instance, is solely caused by low serotonin levels, instead believing it is linked to a combination of biological, genetic, environmental, and psychosocial factors — including the gut-brain axis.

Taylor said, based on her research, the following gut-friendly lifestyle changes could help those with mental health issues to maintain a more stable mood after their symptoms improve — with therapy, drugs, or time — and could prevent particularly serious symptoms in people who are predisposed to them.

1) Eat a nutritious diet that fits with your lifestyle

Certain diets and foods can make your brain and your gut bacteria "very happy," Taylor said.

These include the Mediterranean diet and vegetarianism, and fermented foods such as kefir, kimchi, sauerkraut, and pickles preserved using natural processes instead of vinegar.

Look for the words "naturally fermented" on labels and bubbles in the liquid when you open the jar, which signal that there are live organisms inside, Taylor said.

"At the end of the day, as long as you're eating healthy and getting the right balance of essential nutrients, there's no one magic diet, just as long as it's a reasonable diet that people feel well when they eat it," she said.

A 2020 review of studies published in the journal BMJ suggested an anti-inflammatory diet, meaning high in fiber, polyphenols, and unsaturated fatty acids, could help to reduce depressive symptoms, but that doesn't mean that a poor diet causes depression.

BI has previously reported on how to start eating healthily.

2) Consider taking probiotics

After someone's mental health improves, emerging evidence suggests probiotics could help to maintain gut flora and prevent further symptoms, Taylor said — although it's hard to measure how well a treatment prevents something.

According to the National Center for Complementary and Alternative Medicine, while probiotics have shown promise for treating gastrointestinal issues, we still don't know which specific ones are helpful, how much to take, or who might benefit from them.

But Taylor said she knows anecdotally of people feeling better and having more stable moods with probiotic use. "At the end of the day, there's probably no harm," she said. "And if it helps, it helps."

3) Avoid ultra-processed foods

Taylor said that trying to avoid ultra-processed foods might be helpful for people who are predisposed to conditions such as depression and anxiety.

A 2022 meta-analysis published in the journal Nutrients found that across 17 studies involving 385,541 participants, those who ate more UPFs were at a higher risk of experiencing depressive symptoms.

The researchers suggested that this could be because additives found in UPFs, such as emulsifiers and artificial sweeteners, could disrupt how the body makes and releases chemicals that regulate mood, including dopamine and serotonin.

They also suggested that UPFs could change the way the gut microbiome works and cause inflammation, which has also been linked to mental health issues.

Bonus tip: Don't take antibiotics unless a doctor prescribes them

You should take antibiotics when prescribed by a doctor, Taylor said.

But it's helpful to be aware that they can strip the gut of essential bacteria. When there is "nothing else in your system that replicates what those particular bacteria do," it can cause gastrointestinal issues, Taylor said.

"We've become a society that really likes to take antibiotics for everything," Taylor said. Antibiotics can help treat bacterial infections, but sometimes people take them when an infection could go away on its own.

The Centers for Disease Control and Prevention encourages healthcare providers to use antibiotics sparingly to prevent antimicrobial resistance and an unbalanced gut microbiome.

• Jonathan Wolf was a tech exec who ate a lot of ultra-processed foods before cofounding a nutrition company.
• Wolf improved his diet by making small changes over a few years.
• They include eating fewer UPFs and switching from milk to dark chocolate.

When Jonathan Wolf co-founded the nutrition company ZOE eight years ago, his diet was "not great." He was eating lots of ultra-processed food and tons of sugar, he told Business Insider.

But he began making incremental changes to his diet in 2017, after he met ZOE co-founder Tim Spector, an epidemiologist who studies nutrition and gut health at Kings College London.

Wolf was previously the chief product officer at an advertising tech company. Spector made him aware of how he could improve his diet, including by caring for his gut microbiome, or the microorganisms that live in the gastrointestinal tract. Evidence suggests that a diverse gut microbiome, partly achieved by eating fibrous and fermented foods, is linked to better physical and mental health.

Here are the positive steps Wolf took.

1) Eating fewer ultra-processed foods

In the last 18 months, Wolf has become more aware of and reluctant to eat ultra-processed foods, he said. UPFs are made using industrial processes, and can contain additives such as preservatives and emulsifiers. They were linked to 32 health problems in a recent study, but the authors said further research is needed to confirm there is a link between UPFs and poor health.

Wolf tries to eat fewer UPFs, including by avoiding artificial sweeteners or foods at restaurants that are likely to be ultra-processed.

"We're eating these foods that are made with ingredients that have never been available in the kitchen, that our bodies have never been exposed to before. Whereas our grandparents were eating zero ultra-processed foods," he said. "I suspect it's going to turn out to be a huge part of the health crisis that we're having."

It can be hard to cut out UPFs entirely because they are ubiquitous, particularly in Western countries. Nichola Ludlam-Raine, a dietitian, previously told BI how they can be incorporated into a healthy diet.

2) Shifting focus from excluding to adding foods to his diet

Wolf had stopped eating foods that he was led to believe weren't healthy, such as gluten.

But research on the gut microbiome published in 2021, which ZOE was involved with, showed that a more diverse gut microbiome was associated with better markers of health, including lower blood pressure and a lower chance of having a fatty liver.

Participants who ate a variety of healthy, plant-based foods had more diverse gut microbiomes, the study found.

Wolf realized he needed to eat more whole foods to increase the diversity of his diet and, therefore, his gut microbiome.

3) Working up to eating 30 plants a week

Spector was part of a 2018 American Gut Project study into how many types of dietary fiber, found in plants, are needed for a diverse microbiome. Fruits and vegetables were factored in, as well as other plant-based items such as spices.

It concluded that 30 plants a week appeared to provide enough, which Wolf tries to aim for.

"I did not get there in one step. In fact, it took me years to increase to 30. But I did it steadily, and I think the biggest thing that helped was the realization that tinned food and frozen food can actually be really healthy," he said.

He tries to keep nutritious foods on hand, such as frozen spinach, canned beans, and nuts, so he can easily throw together a meal that contains at least a few plants.

4) Gradually switching from milk to dark chocolate

Wolf was pleased to discover that he could still eat chocolate every day as part of a healthy diet.

"If you're eating a really high-quality dark chocolate, there's a lot of science that says that's actually good for you," he said, partly because it counts as one of your 30 plants a week, contains fiber, and is fermented.

He slowly transitioned from eating milk chocolate, to 50% cocoa, to 60%, and all the way up to 90%. Dark chocolate contains antioxidants, fiber, and polyphenols.

5) Eating fewer foods that spike his blood sugar

Wolf cut down on foods that spiked his blood sugar particularly high, specifically white bread and tea with lots of sugar.

Blood sugar spikes are a safe and necessary part of digesting food. But having consistently high or low blood sugar can lead to a higher risk of chronic diseases, Sarah Berry, professor of nutritional sciences at King's College London, previously told BI.

Wolf replaced white bread with rye bread because it didn't spike his blood sugar as high, and gradually reduced the amount of sugar in his tea.

ZOE sells continuous glucose monitors, which were originally developed for people with diabetes to track their blood sugar levels. However, experts are split on whether they are useful for non-diabetics, and fear they may lead to people avoiding certain foods unnecessarily.

• Eating a variety of fiber-filled foods is linked to better gut health.
• Christina Soteriou, a Cypriot chef, uses a wide range of plants in her recipes for gut health.
• She shared three plant-based recipes that will help you eat more veggies, fruits, and legumes.

For Christina Soteriou, a plant-based chef who grew up in the Mediterranean, healthy eating habits like loading her plate with leafy greens and lentils are second nature. But as she's learned more about gut health in recent years, getting a variety of plants into her diet has become a priority too.

Before moving to London at the age of 18, Soteriou spent most of her childhood in Cyprus, where she became accustomed to following the Mediterranean diet, recently ranked the healthiest way to eat for the eighth year in a row by the US News and World Report.

The eating plan emphasizes a whole-food diet of fresh fruits and vegetables, legumes, whole grains, and healthy fats such as extra virgin olive oil and fish, which leaves less space for ultra-processed foods, refined sugar, and red meat.

Research has linked the Mediterranean diet to many health benefits, including a lower risk of cardiovascular disease and maybe even a longer life. Emerging evidence has also found a link between the diet and gut health.

The gut microbiome, the trillions of microbes that live in the gut lining and are thought to impact our overall health in myriad ways, feeds on the dietary fiber we get from eating plants. Experts believe that the more plants we eat, the healthier our microbiome is.

"I've really tried to focus on gut health and varying my nutrients," Soteriou told Business Insider.

She shared three high-fiber recipes from her new cookbook "Big Veg Energy."

Whipped pea, artichoke, and Za'atar with new potatoes

Serves two to four

30 minutes

Ingredients:

• 700g new potatoes
• 150g asparagus spears
• 100g Jarred marinated artichokes
• 35g arugula
• 100g frozen peas, defrosted
• 1 teaspoon Dijon mustard
• Juice of 1⁄2 lemon
• 1 tablespoon olive oil, plus extra for drizzling
• 2 tablespoons Za'atar
• 2 tablespoons toasted sesame seeds (optional)
• 8—12 mint leaves
• 100g vegan feta or tofu
• Salt and freshly ground black pepper

For the whipped pea and artichoke purée:

• 300g frozen peas, defrosted
• 100g Jarred marinated artichokes, plus 2—3 tablespoons of their oil
• 3 tablespoons lemon juice
• 1 teaspoon Dijon mustard

Method:

1. Bring a large saucepan of salted water to the boil. Add the potatoes and boil for around 15 minutes or until just cooked through. Take care not to overcook; they should be firm but just soft enough to poke your fork through without resistance.

2. While the potatoes are cooking, add the asparagus spears to the saucepan for two minutes, then remove them with tongs and place them in a colander. Rinse under cold running water to stop them cooking, then set aside.

3. When the potatoes are done, drain them and set them aside in a colander to steam dry.

4. To make the whipped pea and artichoke purée, blend all the ingredients in a small food processor (which will give you a chunky texture) or a blender (for a smooth texture). Season to taste with plenty of salt and pepper.

5. Cut the potatoes into bite-sized pieces. Cut the asparagus spears into 3cm pieces. Thinly slice the artichoke pieces.

6. Combine the potatoes, asparagus, artichokes, rocket, and peas in a large bowl. Add the Dijon mustard, lemon juice, and olive oil. Toss to combine, and season well to taste.

7. To assemble, spoon plenty of the whipped pea mixture onto a plate. Top with the potatoes and vegetables, then drizzle with a little more olive oil, and sprinkle over the za'atar and sesame seeds, if using. Tear over the mint leaves and crumble on the vegan feta or tofu, then serve.

Lemony sunflower seed dip

Serves two

30 minutes

Ingredients:

• 200g sunflower seeds, plus extra to serve
• 200g plain vegan yoghurt
• 80ml lemon juice
• 1 teaspoon olive oil
• 4 teaspoons nutritional yeast
• 1 teaspoon flaky sea salt

For the toppings:

• Olive oil
• Pinch of sumac or paprika
• 1 tablespoon sunflower seeds
• 1 tablespoon mint leaves, finely chopped

Method:

1. Tip the sunflower seeds into a bowl and pour over enough boiling water to cover. Leave to soak for at least 25 minutes (soak for at least two hours or overnight if your blender is not a high-speed one).

2. Drain the soaked sunflower seeds and add them to a blender, along with the yogurt, lemon juice, olive oil, nutritional yeast, and salt. Blend until smooth. You may have to keep scraping down the sides of the blender to make sure everything is combined. Add a little more yogurt if your blender still can't get it smooth.

3. Taste and season again if needed, adding more lemon or nutritional yeast according to your preference.

4. To serve, spread the dip over a shallow bowl or plate and pour over a generous drizzle of olive oil. Top with a sprinkle of sumac, followed by the sunflower seeds and mint.

5. This will keep for three to four days in a sealed container in the fridge.

Crushed spiced squash with hazelnut gremolata

Serves two as a min, four as a side

45 minutes

Ingredients:

• 1 small butternut squash (about 750g)
• 1 teaspoon fennel seeds
• 1 teaspoon coriander seeds
• 1 teaspoon cumin seeds
• 1⁄2 teaspoon ground ginger
• 1⁄2 teaspoon smoked paprika
• 3 tablespoons olive oil
• 400g can of chickpeas
• 200g giant couscous (or use brown rice or another whole grain)
• 100g plain vegan yogurt (or soy or oat)
• 1⁄4 tablespoon chile flakes (optional)
• Salt and freshly ground black pepper

For the hazelnut gremolata:

• 30g hazelnuts
• 1 big garlic clove
• 40g flat-leaf parsley
• 1 lemon
• 75ml olive oil

Method:

1. Preheat the oven to 425°F.

2. Peel and halve the squash, and remove the seeds. Cut the flesh into 2cm cubes and spread over a large roasting tray.

3. Combine the fennel, coriander, and cumin seeds in a mortar with the ginger and paprika, and grind into a rough crumb. Sprinkle this over the squash, then add two tablespoons of the olive oil. Season well with salt and pepper and toss to combine.

4. Roast the squash for 15 minutes, then drain the chickpeas and add them to the roasting tray, along with the remaining tablespoon of olive oil. Mix well and roast for another 15 minutes until the squash is soft and starting to char in places.

5. Meanwhile, cook your couscous in a saucepan of boiling water for eight minutes. Drain and rinse quickly to prevent it sticking.

6. To make the gremolata, lightly toast the hazelnuts in a dry frying pan. Mince the garlic and roughly chop the parsley. Zest and juice the lemon, reserving the zest for later.

   Add the lemon juice, garlic, parsley, hazelnuts and 30ml of the olive oil to a small food processor and blitz until you have a chunky paste. Pour this into a bowl and add the remaining 45ml of olive oil. Season with salt and pepper to taste. The mixture should be bright, zesty, and crunchy.

7. Once the squash is cooked, use a fork or a potato masher to mash about half to three-quarters of the squash and chickpeas in the pan you cooked them in.

8. Pour the couscous into a large bowl or platter and mix through the crushed squash mixture. Add the gremolata and a few dollops of yogurt. Finish with the reserved lemon zest and a sprinkle of chile flakes, and a final drizzle of olive oil, if you like.

• Snacking can be an easy way to eat more fiber and boost gut health.
• Fiber helps fuel the "good" microbes in the gut, which influence overall health.
• Emily Leeming, a gut health scientist and chef, snacks on dark chocolate and fruit.

Snacking can be a great way to eat more fiber and look after your gut health, Emily Leeming, a dietitian and gut microbiome researcher at King's College London, told Business Insider.

The gut microbiome is the name given to the trillions of microbes that live in the colon lining, which studies have linked to our overall health — from the immune system to the brain.

Fiber, found in foods such as fruit, vegetables, whole grains, and beans, fuels the "good" microbes in the gut. And studies suggest that it helps create a more diverse microbiome, an indicator of a healthy gut. The Dietary Guidelines for Americans recommends that adults eat 22 to 34 grams of fiber each day.

Snacks make up around 20% of the average person's energy intake, Leeming said, so choosing more nutritious foods can be a "great strategy to making big inroads for our health."

"When you're feeling hungry, you can think, 'Okay, can I get at least five grams of fiber in a snack?'" Leeming, a trained chef and the author of "Genius Gut: The Life-Changing Science of Eating for your Second Brain," said.

Leeming shared her four go-to snacks that boost her gut health.

Fresh or dried fruit

Fresh or dried fruit is a delicious snack, a great source of fiber, and easy to eat on the go, Leeming said: "I love fruit, I eat a lot of it."

Berries, in particular, are high in fiber, and can be sprinkled on top of a sweet breakfast such as oatmeal or Greek yogurt in seconds, she said.

Dried apricots, which contain seven grams of fiber per 100 grams, are another of her favorites.

Nuts

As well as containing heart-healthy fats and plant protein, nuts are high in fiber.

They contain around seven to nine grams of fiber per 100 grams and typically require no prep, making them the perfect quick, gut-friendly snack.

Leeming keeps a jar of mixed nuts by the kettle in her kitchen, so she can eat them while she waits for it to boil.

"The things that I want to eat more of, I keep in my line of sight. That just visually prompts you to go for them as a first step," she said.

Crudités and dip

Leeming likes to keep plant-based dips such as hummus or guacamole, and some chopped-up veggies in the fridge so she can grab them when she's feeling peckish.

"Just having some snacks that are more healthy and easily available really helps," she said."I really focus on things that are easy and simple that you just don't have to do lots of mental logistics to kind of make happen."

Vegetables contain fiber, as well as the chickpeas in hummus, and the avocado in guacamole.

Dark chocolate

85% strength dark chocolate is surprisingly high in fiber, Leeming said: "It's about 11 grams of fiber per 100 grams."

She loves to have two squares paired with some fruit as a snack. "That's making a significant contribution toward that 30 grams of fiber a day that we need," she said.

Dark chocolate, which contains antioxidants, also has other health benefits. A recent study based on around 110,000 nurses, published in the BMJ, found that those who consumed at least five servings of dark chocolate a week had a 21% lower risk of type two diabetes from the baseline than those who had none or rarely ate chocolate.

The authors said this could be because dark chocolate is high in epicatechin, a polyphenol that research suggests could help prevent metabolic disease.

• Evidence suggests that fermented foods such as kimchi can boost gut health.
• A diverse microbiome is linked to overall good health.
• The gut-health researcher Emily Leeming uses tricks such as adding kefir to salad dressing.

Fermented foods such as kimchi and pickles are great for supporting the gut microbiome, the trillions of microbes that help shape our health.

Made when live bacteria or yeast are added to ingredients such as tea, milk, or vegetables, fermented foods contain probiotics, the "good" bacteria in our guts. The microbiome contains "good" and "bad" bacteria. Eating a diverse range of fiber-packed plant foods feeds the good ones, while ferments are thought to introduce new "good" elements to the microbiome.

Emily Leeming, a microbiome researcher at King's College London, dietitian, and former private chef, told Business Insider that she tries to eat fermented foods every day.

Emerging research suggests that fermented foods increase the diversity of the gut microbiome, a key marker of a healthy gut, and reduce the risk of cardiovascular disease and type 2 diabetes, according to a 2022 review in the journal Nutrients.

"We are really understanding more and more that this collection of a hundred trillion microorganisms are influencing every aspect of our health," said Leeming, the author of "Genius Gut: The Life-Changing Science of Eating for your Second Brain." And what we eat has a major influence.

Leeming shared four ways she adds fermented foods to her daily diet.

Using kefir instead of yogurt

Kefir is a fermented milk drink similar to yogurt but thinner in consistency and with more live microbes.

For this reason, Leeming tends to opt for kefir anytime a recipe calls for yogurt. She might put it in a smoothie or in overnight oats, for example.

"Kefir I find really easy to incorporate in different things," she said.

Keeping fermented veggies in the fridge

Leeming keeps fermented veggies such as sauerkraut, kimchi, and jars of fermented beetroot and carrots in her fridge and adds them to a dish whenever she thinks it'll enhance the flavor.

"I like to have a mix of different ones in the fridge as they last a long time and it means there's more flavourful variety rather than eating the same ones all the time," she said.

She likes to mix kimchi into rice-based dishes, for example, or sprinkle some fermented veggies on top of avocado toast or eggs.

"Nobody wants to eat kimchi on its own. You want to think how it fits into your dish," she said.

David Zilber, the former director of fermentation at the celebrated restaurant Noma, previously told BI that he always keeps pickled jalapeños, sauerkraut, and kimchi in his fridge.

Changing up salad dressings

As a chef, Leeming considers the taste of a meal to be equally as important as its nutritional value. One of her hacks for making any vegetable delicious is making a flavorful salad dressing.

For this, she always has a good quality extra-virgin olive oil in her store cupboard. EVOO is high in polyphenols, a compound responsible for the pigment in lots of plants that research suggests gut microbes break down into beneficial molecules, she said.

And to make it even more gut-friendly, she often adds kefir.

Using miso as a soup base

Miso is a paste made from fermented soybeans. Leeming suggested using it as a base for soups for "that umami, fermented kick."

Marika Mancino, a dietitian, previously told BI that miso is also a great lower-sodium swap for stock.

• Gut health is a key cornerstone of our overall health as it can affect many bodily systems.
• A diet high in fiber, fermented foods, and polyphenols can help support a healthy gut microbiome.
• Emily Leeming, a gut health expert and dietitian, sees her breakfast as a chance to boost her fiber intake.

A gut health scientist and dietitian shared the two breakfasts she often eats to help boost her gut microbiome.

Gut health is a key cornerstone to overall health because it is thought to influence everything from the immune and endocrine systems to the brain, Emily Leeming, a gut microbiome researcher at King's College London and a former private chef, told Business Insider. Experts consider a gut that contains a diverse community of microbes healthy.

What's great about the gut microbiome, the name for the trillions of microbes that live in the gut lining, is that what we eat shapes it, Leeming, who is based in London and the author of "'Genius Gut: The Life-Changing Science of Eating for your Second Brain," said.

Eating a diet packed with fiber, polyphenols — the compounds that contribute to the pigment in many fruits and vegetables — and fermented foods, can help those microscopic bugs thrive, she said.

Leeming sees her first meal of the day as a key time to boost fiber by adding some veggies or fruits if she's preparing something sweet. She also tries to get around 20 to 30 grams of protein in each meal, including breakfast.

"It's those simple small changes that we make on a regular basis that actually have the most impact," Leeming said.

She combines all those elements while making her meals taste great.

"Food has to taste delicious, otherwise life is sad," she said.

Roasted veggies and eggs on rye pumpernickel toast

Leeming is a big fan of pumpernickel rye bread as it's high in fiber. "For one slice, it's around seven grams of fiber," she said.

She loves to pair it with roasted vegetables and eggs. She places them all in a small oven dish and roasts them for 15 minutes at 392 degrees Fahrenheit.

"At the moment, I've been doing zucchini and baby tomatoes," she said, adding that she mixes in harissa and crumbles feta cheese on top.

At the end, she sprinkles some mixed seeds on top for added fiber and protein.

"What's really surprising to many people is that whole grains, beans, nuts or seeds actually tend to contain much more fiber than fruits and vegetables, although of course we still need to get fruits and vegetables," she said.

Overnight oats

Overnight oats prepared in batches are another breakfast favorite, Leeming said. She uses rolled oats and adds kefir, grated carrot, apple, blueberries, cinnamon, mixed nuts, chia seeds, and flax seeds.

Leeming's oats contain lots of gut-loving ingredients. Chia seeds feature about 30 grams of fiber per 100 grams, and berries tend to be higher in fiber than other fruits because they contain seeds, she said. They're also high in polyphenols.

She opts for kefir, a fermented milk drink, instead of yogurt because it tends to contain more probiotics, the good microbes.

• An epidemiologist and nutrition expert eats at least three fermented foods each day for gut health.
• Tim Spector shared his tips on how to incorporate fermented foods into your diet.
• These include starting small, checking food labels, and "backslopping."

You may have noticed a proliferation of kefir and kombucha in stores lately. Fermented foods are everywhere, but can be a little intimidating to people who aren't used to them.

Tim Spector, a British epidemiologist and cofounder of the nutrition company Zoe, eats at least three different types of fermented foods every day to aid his gut health.

Research on fermented foods is still developing, but, according to a 2022 review in the journal Nutrients, studies suggest that they can reduce risks of cardiovascular disease and type 2 diabetes, and increase the diversity of bacteria in the gut. The gut thrives on a varied diet, so this diversity is important for digestive and overall health.

Spector told Business Insider how he incorporates fermented foods into his diet.

Start small

"Little and often" is the best way to start adding fermented foods to your diet, Spector wrote in his cookbook "Food For Life," which is due to be published in the US in 2025.

This allows you to get used to the taste and your gut to get used to all the new bacteria.

Spector recommends adding a tablespoon of different fermented foods to your cooking — for example, kimchi in a stew for "flavor and crunch," or kefir to a soup for "creaminess and tang."

This chimes with what other experts told BI: Tanzil Miah, a dietitian specializing in gut health, said adding kimchi or sauerkraut to sandwiches or salads, and using yogurt as a sauce or marinade are easy ways to add fermented foods to what you're already eating.

Check out labels of shop-bought fermented foods

"My advice to the fermenting newcomer is to find some commercial fermented products you enjoy and slowly work up to fermenting your own," Spector wrote in "Food For Life."

When buying shop-bought fermented foods, such as kefir, kombucha, sauerkraut, or kimchi, he recommends looking for products that are:

• Low in added sugar.
• Have few/no chemical additives.
• Not pickled in vinegar, which kills live microbes.

Then make your own

When you're ready, Spector said you can expand the scope of fermented foods away from just pickles and kefir. He now makes his own homemade labneh and a fermented mushroom-and-garlic spread, for example.

Making fermented foods at home is also great for the environment and your wallet because it reduces food waste, he said.

And it's easy. "You can ferment just about any plant," he said, using only salt or honey.

BI previously reported a Michelin-star chef's techniques for making homemade kimchi, sauerkraut, and pickles.

Or, Spector said, you can make your own kefir from the dregs of a store-bought bottle with a technique called "backslopping." To backslop kefir, add a tablespoon of good-quality kefir to a bottle of full-fat milk, leave it at room temperature until it thickens, and then store in the fridge.