Eat 30 different plants for a Healthy Microbiome
Increasing the variety of plant foods from the standard New Zealand diet is one of the most powerful steps you can take to support your gut microbiome. This supersedes taking supplements, probiotics, or avoiding groups of foods. Large human studies, including the American Gut Project, have shown that people who eat 30 or more different plant foods each week have significantly more diverse gut bacteria than those who eat fewer than ten. This matters because the typical New Zealand diet is relatively low in fibre and dominated by a small number of plant foods. Yes, we're good with apples, bananas, kumara, broccoli and carrots with a side of frozen peas, most dinners will have onion and for a lucky few garlic will make an appearance, fresh or granules, sound familiar? When we limit the range of plants, we limit the food sources for beneficial microbes in the gut. When you expand the diversity of plants you eat, and this includes vegetables, fruits, whole grains, legumes, nuts, seeds, herbs, and spices, you feed a wider range of microbes.
These microbes produce short‑chain fatty acids that support gut barrier health, regulate immune responses, and help lower our inflammation.
Your gut microbiome is a living ecosystem made up of trillions of bacteria, fungi, and other microbes. Different microbes specialise in digesting different types of fibres, polyphenols, and plant compounds. When your diet includes only a narrow range of plant foods, which is common in New Zealand, where many of us rely on the same few vegetables and grains, only a small subset of microbes are fed.
The American Gut Project, one of the largest microbiome studies to date, analysing data from more than 10,000 people across the US, UK, and Australia, found that the strongest predictor of a healthy, diverse gut microbiome wasn’t probiotic supplements or fermented foods, it wasn’t how much alcohol you drank or avoided, it wasn’t even your history of antibiotic use, but simply the number of different plant foods eaten each week. Greater plant variety means greater microbial diversity, and microbial diversity is the key marker of gut resilience and overall digestive health.
Microbial diversity is critically important because it is associated with:
Better digestion and bowel regularity
Stronger immune function
Lower inflammation
More stable mood and energy
Better metabolic health
Basically, a diverse microbiome is more resilient, adaptable, and capable of producing beneficial compounds that support your whole body.
If you still feel the hangover of the 90’s when counting calories or points was promoted and have felt the lasting damage on your relationship with food, then this can be a positive shift in your attention. When we teach communities to focus on the number of plants they have access to, we’re celebrating the benefits of increasing these foods, no limiting required. All gold stars and no time out or guilt trips.
Plants to Feed Your Microbiome
Plant foods contain dietary fibres, resistant starches, and polyphenols, all of which act as fuel for your gut microbes.
Fibre and resistant starch
Fibre is not digested by you; that’s what defines it, it is instead digested by your microbes. When they ferment fibre, they produce short‑chain fatty acids (SCFAs). In the clinic I call these “gold dust” because you just can’t supplement them, you need your lovely little microbes to make them, and this Short Chain Fatty Acid Gold Dust is the magic that changes everything for our health. These compounds are the proof we are dependent on our gut microbiome, because the gold dust is essential for:
Maintaining the gut barrier
Regulating immune responses
Reducing inflammation
Supporting metabolic health
Reviews in Nature Reviews Microbiology actually describe SCFAs as the key mediators between diet, microbes, and human health, influencing immune pathways and gut integrity.
The American Gut Project noted that participants who ate more than 30 plant foods per week had more bacteria that produce short‑chain fatty acids ‘gold dust’.
Polyphenols
Polyphenols are a large family of plant compounds found in berries, herbs, spices, tea, cocoa, olives, nuts, seeds, and colourful vegetables. Like fibre humans don’t absorb most polyphenols directly, instead, they travel to the colon, where gut microbes metabolise them into bioactive compounds. This two‑way relationship is one of the most elegant examples of diet–microbiome synergy.
Microbes break down polyphenols into smaller metabolites that have anti‑inflammatory and antioxidant effects (think glowing skin and less joint pain).
Polyphenols, in turn, shape the microbiome, encouraging the growth of beneficial species such as Akkermansia, Bifidobacterium, and various ‘gold dust’ producers.
This creates a positive feedback loop: more polyphenols → healthier microbes → more beneficial metabolites
How Much Fibre Do Most People Need?
Most adults benefit from aiming for around 25–30g of fibre per day from food.
The challenge is that the standard New Zealand diet often falls short of this. Many people consume less than half of the recommended amount, which limits SCFA production and reduces microbial diversity.
Simply focusing on counting and increasing plants in the diet is one of the easiest ways to naturally increasing fibre, and almost all health parameters.
When 5+ a day is holding us back.
I actually love this public health strategy. It’s simple, it’s positive, and it’s coming from exactly the right place. At its heart, it’s about getting more plants into the everyday diet of every New Zealander, something we can all agree is needed. But I’m ready to take it a step further with my clients. It’s not just about adding some plants; it’s about adding many different plants. Diversity is where the real microbiome magic happens. When we shift the focus from “eat more plants” to “eat a wider variety of plants,” we move from a broad guideline to a targeted, evidence‑based strategy that genuinely changes gut health.
So rather than just eat more apples each week, let’s eat apples, kiwifruit, berries, persimmon and feijoa. You could eat broccoli every day, but if that’s the only vegetable you eat, your microbiome will still be under‑fed.
So, if we’re counting to 30 over the course of a week, how much counts?
Vegetables
Leafy greens: ~1 cup raw or ½ cup cooked
Cruciferous vegetables (broccoli, cauliflower, cabbage): ~1 cup
Starchy vegetables (kumara, potato, pumpkin): ~½ cup
Fruits
Whole fruit: 1 medium piece or 1 cup chopped
Berries: ½–1 cup
Grains and Legumes
Oats, quinoa, brown rice, barley: ~½ cup cooked
Beans, lentils, chickpeas: ~½ cup cooked
Nuts and seeds
Nuts: a small handful (around 30g)
Seeds: 1 tablespoon
Herbs and spices
Herbs: 1–2 tablespoons fresh
Dried Spices: 1-2 teaspoons
Each different plant counts toward your weekly total. For example, basil and parsley are two separate plants; almonds and walnuts are two separate plants; oats and quinoa are two separate plants.
If You Don’t Eat Much Fibre Now, Start Slowly
If your current fibre intake is low, increasing it too quickly will likely cause bloating, gas, or constipation, the diarrhea and a world of discomfort. This is not harmful, and certainly not cause to stop, it’s simply your microbes adjusting, but it can be unpleasant, and isn’t necessary.
A gentle approach works best:
Increase fibre gradually over several weeks
Add one new plant food at a time
Drink plenty of water
Include fermented foods to support microbial balance
Mix cooked and raw vegetables to ease digestion
Use “plant boosters”
Add herbs to salads
Add seeds to breakfast
Add beans to soups
Add extra vegetables to pasta sauces
Your microbiome adapts quickly. Within days to weeks of increasing plant diversity, beneficial microbes begin to flourish.
In NZ we have a habit of building our meals around the protein component. What’s for dinner Dad? “Lamb Chops” But we can absolutely build meals around plants. Start with vegetables, legumes, or whole grains, then add protein. Let the chicken be the side dish, and the roast vegetables take centre stage, with some roasted garlic and beetroot, tossed in parsely butter.
Try new varieties
Swap your usual apples for pears, your usual lettuce for rocket, your usual pumpkin for beetroot. Instead of frozen blueberries, get the mixed berries.
Rotate your grains
Instead of always choosing pasta or rice, try quinoa, barley, buckwheat, or oats.
Explore legumes
Chickpeas, black beans, lentils, butter beans — each one feeds different microbes.
Use spices generously
Turmeric, cinnamon, cumin, coriander, ginger, paprika, each one counts as a separate plant.
What Happens in Your Gut When You Increase Plant Diversity?
When you feed your microbes a wider range of fibres and polyphenols:
More microbial species grow
SCFA production increases - Mmmmm gold dust!
The gut barrier strengthens
Immune responses become more balanced
Inflammation decreases
Digestion becomes more regular
Metabolic health improves, you may even lose weight
These changes ripple outward, affecting your energy, mood, skin, hormones, and long‑term health.
The standard New Zealand diet tends to be:
Low in fibre
Low in plant diversity
High in refined grains
Increasing in ultra‑processed foods
This pattern limits microbial diversity and contributes to inflammation, digestive issues, and metabolic challenges. I see it in clinic in your skin, your hay fever, your cholesterol levels, your blood work.
But eating a diverse plant‑rich diet is one of the most powerful tools you have to support your microbiome and therefore your health.
