III.3

Plant diversity: the weekly 30

What counts is not how much of one thing you eat, but how many different plants you eat in total. This week you'll meet the principle of 30 plants a week and start collecting diversity — the secret of a varied, resilient gut flora.

Összefoglaló

Last week you learned that fibre is your flora's food. Now comes the next step: it is not only the amount of fibre that matters, but also the diversity of its sources. A healthy gut is home to many different bacteria living together, and each has its own favourite food. The more kinds of plants you eat, the more kinds of bacteria you feed — and the stronger and more resilient your flora becomes. This week you'll start collecting 30 different plants a week, playfully and gradually.

Why diversity, not quantity?

Think of your gut flora as a forest. A forest where only one kind of tree grows is fragile: a single pest can level it. A forest made up of many kinds of trees, shrubs and fungi, by contrast, is resilient — if one element weakens, the others take over its role. Your gut flora^[G] works exactly the same way: the more kinds of bacteria living in it, the harder it is for a pathogen, such as Clostridioides difficile, to overgrow and upset the balance.

Different bacterial species like different foods. One prefers the fibre in apples, another the fibre in beans, a third the fibre in onions, a fourth the fibre in berries. If you always eat the same few foods — however healthy they are — you feed only a few species, while the rest go hungry. That is why the question is not how much of one thing you eat, but how many kinds you eat in total.

This is where the principle of 30 plants a week comes in: the goal is to take in at least thirty different kinds of plants in a week. At first this seems like a lot, but it is easier than you'd think: it includes vegetables, fruit, wholegrains, legumes, seeds, nuts — even herbs and spices. A soup with five kinds of vegetable is already five marks on the list.

How to collect your weekly 30?

The best approach is to treat this as a game, not a chore. Make a simple list — on paper or on your phone — and over the course of the week draw a line for every new plant you eat. An apple, a handful of oats, a bunch of parsley, a few walnuts: each is a separate mark. The counting itself is motivating, and you'll notice how easy it is to broaden the list with small swaps.

The secret of broadening lies in small swaps and additions. Put four vegetables in the soup instead of the usual two. Sprinkle a few seeds on your morning oats. Alongside your usual apple, sometimes choose a pear, some berries, a banana. Season your food with fresh or dried herbs — these count too. On no single day do you have to do much; yet by the end of the week the list will be surprisingly long.

Keep in mind what you learned about fibre: build diversity gradually and gently as well. If some new plant causes bloating, take it in a smaller portion, or cooked or steamed. The goal is not to dump thirty new foods into your gut in a single day, but for your plate to grow more colourful slowly and enjoyably over the week. It is this variety that makes your flora resilient in the long run.

The power of colour: polyphenols

There is a particular reason why it is worth aiming for colourful plants specifically. The vivid colour of plants — the deep blue of berries, the red of pomegranate, the brown of cocoa — comes largely from natural compounds we call polyphenols. These are not simply colourants: once they reach the large intestine, they become food for the good bacteria, support a varied flora, and also have an anti-inflammatory effect — that is, they help calm the inflammation that a prolonged infection leaves behind.

You don't have to buy or count polyphenols separately — they are simply present in the tastiest colourful foods. The richest sources are: berries (blueberry, blackcurrant, chokeberry), cocoa and dark chocolate of at least 70% in small portions, green tea, extra virgin olive oil and pomegranate. When you add a handful of blueberries or a cup of green tea towards your weekly 30, you're not just drawing another mark on the list — you're also nourishing your flora with these protective compounds. So the rule is simple: the more colourful the plate, the more polyphenols.

If you'd like guidance, the book's Plant Calendar (Appendix F) suggests a specific plant source for each day from day 15 onwards — at the start, soluble-fibre sources that support firmer stools, then an ever-wider selection, so that reaching the weekly 30 comes easily. Detailed descriptions of individual plants and their microbiome effects are contained in the sister publication Food Sources, which is continually expanding.

🩺 Klinikai blokk

Microbial diversity (species richness and evenness) is one of the key indicators of an ecosystem's resilience; CDI is characteristically a low alpha-diversity, dysbiotic state. The link between dietary plant diversity and microbiota diversity has been demonstrated at the population level: increasing the number of dietary plant species is associated with enrichment of the commensal community. Fibre sources with differing carbohydrate structures select for different bacterial populations, so variety supports a broader functional repertoire — including more SCFA-^[G] and butyrate-producing^[G] strains.

Colonisation resistance, which limits the overgrowth of C. difficile, is a collective property of the diverse, metabolically active community (Reed and Theriot, 2021 [365]): both competition for nutrients and niches and the production of secondary bile acids are diversity-dependent. The loss of diversity observed with a low-fibre, monotonous diet (Sonnenburg et al., 2016) can therefore be read as a direct relapse-risk factor in the post-FMT period.

Day 31 – Start the list

Today you begin collecting the weekly 30. The task is simple: write down everything you ate today from a plant source, and count how many kinds.

Make a list (paper or phone) and record every plant food of the day on it
Put at least two kinds of vegetable or fruit into one meal
In the evening, count how many kinds of plant you ate today — this is your starting point
Diary: stool count, Bristol, bloating, fluids; the number of plant species

Day 32 – Small swaps

Today we don't force in new foods; instead we make the familiar ones more varied with a few small swaps.

Add an extra plant to a familiar dish (e.g. extra vegetables to soup, seeds to salad)
Alongside your usual fruit, choose a different one as well
A spice or fresh herb is also a mark on the list — use them freely
Add a polyphenol-rich, colourful source: a handful of berries, a cup of green tea or a square of 70% dark chocolate
Diary: stool count, Bristol, bloating, fluids; today's new plant species

Day 33 – Count and plan

Today is a halfway count: where does your list stand, and what could you add to round it out by the end of the week? A little planning goes a long way.

Look at your list: how many kinds of plant have you reached, and what's missing (seed, nut, legume, berry?)
Round it out with a well-tolerated plant not yet on the list
Plan ahead: at your next shop, choose one or two new vegetables or fruits
Diary: stool count, Bristol, bloating, fluids; the total plant species for the week so far

🍽️ Eating during these days

This week's theme is plant diversity itself, and eating is the practice ground for it: the concrete task across the three days is to start a list of your plant foods (day 31), broaden it with small swaps — extra vegetables in the soup, seeds on the oats, a different fruit, a spice, a handful of berries or a cup of green tea (day 32), then count and plan where the list can be rounded out by the end of the week (day 33). Every meal is an occasion to bring another plant species onto the plate — this is exactly the everyday motion of the weekly 30 principle.

The Plant Calendar (Appendix F) gives specific sources for these days: soaked chia seeds for day 31, ground flaxseed for day 32, cooked beetroot for day 33. These days fall into the calendar's "gradual expansion" (days 31–50) phase, in which we widen the circle towards steamed vegetables, soaked seeds and polyphenol sources. Chia and flaxseed provide soluble fibre (flaxseed also provides omega-3), and cooked beetroot provides root-vegetable fibre and polyphenols — together they increase plant diversity and fermentable fibre intake, which is substrate for fibre-degrading bacteria and, through them, leads to the formation of more short-chain fatty acids, including butyrate; this nourishes the gut lining, and the diversity strengthens the flora's resilience.

📊 Adat

Record daily this week:

DiffBiome dose (capsules/day) and LOT number, if the course is still ongoing;
daily stool count;
stool Bristol scale (1–7), with 3–4 as the target;
bloating (0–5);
bloody stool (yes/no);
fluid intake (litres);
the daily and cumulative weekly number of plant species;
wellbeing (1–5).
Movement: type + minutes, step count (target/actual)
Stress level (1–5) and mood (1–5)
Sleep (hours + quality 1–5)

Why does this matter?

A varied flora is a resilient flora — and the simplest source of variety is many kinds of plant in your diet. This week you learned that it is not quantity but variety that counts, and you started collecting the weekly 30 with small swaps, playfully. This variety is one of your best protections against relapse, because the more kinds of good bacteria you feed, the less room is left for the pathogen. Next week we'll take out another powerful tool: fermented foods.

[[REFERENCES]]

References

[365] Reed AD, Theriot CM. Contribution of Inhibitory Metabolites and Competition for Nutrients to Colonization Resistance against Clostridioides difficile by Commensal Clostridium. Microorganisms. 2021. Link

This review examines how commensal Clostridium species mediate colonization resistance against C. difficile. Commensal Clostridia modify primary bile acids into secondary bile acids that suppress C. difficile spore germination and vegetative outgrowth. They additionally produce antimicrobial peptides and short-chain fatty acids that directly inhibit C. difficile and compete for limiting nutrients such as proline, important for C. difficile growth via Stickland fermentation. Loss of commensal Clostridia after broad-spectrum antibiotics is a key mechanistic step toward CDI susceptibility. The authors argue that restoring defined Clostridium consortia is a rational, mechanism-driven alternative to FMT for preventing recurrent CDI.