The 30 Plants a Week Challenge: Does It Work?

Quick answer: Eating 30 different plant foods a week is one of the best-evidenced things you can do for gut health. The target comes from the American Gut Project, which found people eating 30+ plant types weekly had more diverse gut bacteria than those eating fewer than 10. It works — but as a direction of travel, not a magic number. Diversity, fibre and consistency matter more than hitting exactly 30. Many people pair it with probiotics, Akkermansia muciniphila, citrus pectin powder, berberine or TUDCA, though food comes first.

Written by Dr Zeeshan Afzal (MBBS), Medical Doctor and Clinical Content Lead at Welzo. Last reviewed: 28 July 2026.

Related reading: microbiome diversity · best foods for gut health · high-fibre foods UK · prebiotic foods · short-chain fatty acids · gut health in the UK

Table of contents

1. What "30 plants a week" actually means
2. Where the 30 plants a week rule came from
3. Does eating 30 plants a week work? What the evidence says
4. How plant diversity changes your gut
5. Health benefits linked to eating 30 plants a week
6. What counts as a plant point (and what doesn't)
7. How to hit 30 plants a week in the UK
8. A four-week 30 plants challenge plan
9. Doing it on a budget
10. Side effects, risks and who should be careful
11. Do you still need supplements?
12. Five myths about the 30 plants challenge
13. Frequently asked questions
14. References

What "30 plants a week" actually means

The 30 plants a week challenge asks you to eat 30 different plant foods over the course of seven days. Not 30 portions. Not 30 servings a day. Thirty distinct species or varieties, counted once each, across the whole week.

This is a fundamentally different instruction from "five a day". The NHS 5 A Day campaign is about quantity — 400g of fruit and vegetables daily, based on World Health Organization advice. The 30 plants target is about variety. You could technically hit five a day for a year eating nothing but apples, bananas, carrots, peas and tomatoes, and score just five plant points a week.

The other key difference is scope. Five a day counts fruit and vegetables only. The 30 plants approach counts every plant food group: fruit, vegetables, wholegrains, legumes, nuts, seeds, herbs, and spices. That widening of the definition is what makes 30 achievable for ordinary people eating ordinary food.

Why variety, not volume, is the point

Your large intestine hosts trillions of bacteria. Different bacterial species have evolved to break down different molecular structures — the fibre in an oat is chemically distinct from the fibre in a leek, a lentil or a raspberry. Feed your gut one type of fibre and you selectively feed a narrow set of microbes. Feed it thirty and you support a far broader community.

That community breadth is what researchers call microbiome diversity, and it is consistently one of the strongest markers separating healthy guts from unhealthy ones. Low diversity, or gut dysbiosis, is associated with inflammatory bowel disease, obesity, type 2 diabetes and a range of other conditions.

Where the 30 plants a week rule came from

The American Gut Project

The number traces back to a single study: American Gut: an Open Platform for Citizen Science Microbiome Research, published in the journal mSystems in May 2018 by Daniel McDonald, Rob Knight and the American Gut Consortium.

It was, at the time, the largest open-source investigation of the human microbiome ever conducted. More than 10,000 people from the United States, the United Kingdom and Australia posted in stool samples along with detailed food frequency questionnaires. Researchers analysed a subset of roughly 3,500 to 4,000 healthy adults.

What the study actually found

The researchers compared people who reported eating more than 30 different plant types per week against those eating fewer than 10. Three findings stood out:

• Higher microbial diversity. The high-plant-diversity group had a measurably broader range of bacterial species.
• More short-chain fatty acid producers. Using partial least-squares analysis, the team identified enrichment of putative SCFA fermenters including Faecalibacterium prausnitzii and organisms of the genus Oscillospira in the high-diversity group. The statistical signal was strong (ANOVA P = 8.9 × 10⁻³⁹).
• Fewer antibiotic resistance genes. People eating more plant types carried lower levels of certain antibiotic resistance genes in their gut flora.

Faecalibacterium prausnitzii matters here. It is one of the most abundant bacteria in a healthy human colon and a major producer of butyrate, the short-chain fatty acid that feeds the cells lining your colon and helps maintain gut barrier function.

Why 30 and not 20, 25 or 40?

This is the question most articles skip, and answering it honestly matters.

The American Gut Project compared a "more than 30" group with a "fewer than 10" group. It did not test 24 against 30, or 30 against 36. There is no published evidence of a biological cliff edge at exactly 30 plants.

The Microsetta Initiative — the research group that continues the American Gut work at UC San Diego — has said as much directly: 30 is a guideline rather than a rigid threshold, and what matters is overall plant diversity.

So think of 30 as a well-chosen communications target. It sits at the top end of what the original study measured, it is memorable, and it is achievable for most UK households. It is not a number your gut recognises.

Does eating 30 plants a week work? What the evidence says

Short answer: the underlying principle is well supported, the specific number is not, and the mechanism is more complicated than most headlines suggest. Here is the full picture.

The evidence in favour

1. Plant diversity tracks with microbiome diversity. This is the American Gut finding, and it has held up across multiple cohorts. People who eat a wider range of plants have broader, more resilient gut ecosystems.

2. Fibre intake has hard clinical outcome data behind it. A landmark series of systematic reviews and meta-analyses published in The Lancet in 2019 by Reynolds and colleagues pooled 185 prospective studies and 58 clinical trials, covering close to 135 million person-years. Comparing the highest fibre consumers with the lowest, they found a 15–30% reduction in all-cause mortality, cardiovascular mortality, coronary heart disease, stroke, type 2 diabetes and colorectal cancer. Every additional 8g of fibre per day was associated with 5–27% lower risk across those outcomes. Benefit was greatest at intakes of 25–29g daily, with dose-response curves suggesting more may be better still.

3. Eating 30 different plants is a highly effective way to hit that fibre target. UK adults are advised to eat 30g of fibre a day, a recommendation set by the Scientific Advisory Committee on Nutrition in 2015. According to the British Nutrition Foundation, most UK adults manage around 20g or less. HEART UK reports average intake of roughly 19g, with only about 9% of adults meeting the target. Chasing variety naturally pulls fibre upward — see our guide on how to increase fibre.

4. Different plants deliver different bioactive compounds. Beyond fibre, plants supply polyphenols, resistant starch, and micronutrients. A blueberry, a walnut and a chickpea are not interchangeable.

Where the evidence is weaker

The American Gut study was observational and cross-sectional. It cannot prove that eating more plants causes a more diverse microbiome. People who eat 30+ plant types weekly also tend to smoke less, drink less, sleep better, exercise more and have higher incomes. Any of those could contribute.

Diet was self-reported. Food frequency questionnaires are notoriously imprecise, and participants were self-selected volunteers who paid to take part — not a representative population sample.

A randomised trial complicates the story. In 2021, Wastyk and colleagues at Stanford published a 10-week randomised study in Cell. One group increased fibre from roughly 21.5g to 45.1g per day. The other increased fermented foods from 0.4 to 6.3 servings daily. The result surprised the investigators: the high-fibre group showed no cohort-wide increase in microbiome diversity, while the fermented-food group's diversity rose steadily and 19 inflammatory blood proteins fell, including interleukin-6.

The Stanford team's interpretation was that increasing fibre alone, over a short period, may not be enough to raise diversity — possibly because some participants' existing microbes lacked the enzymes to break down the new fibres. Diversity may take longer than 10 weeks to shift, and may need seeding from outside as well as feeding from within.

The honest verdict

Claim	Evidence strength	Verdict
Eating a wide variety of plants supports a more diverse microbiome	Strong observational, plausible mechanism	Well supported
Higher fibre intake lowers risk of heart disease, diabetes and bowel cancer	Very strong — large meta-analyses of trials and cohorts	Well established
30 is a specific biological threshold	None	Not supported — it's a useful target, not a cliff edge
Adding plants alone will rapidly increase microbiome diversity	Mixed — one RCT found no short-term effect	Unclear; combine with fermented foods
You must reach 30 to benefit	None	False — benefits appear on a gradient

Put simply: the 30 plants challenge works as a behavioural tool. It reliably increases fibre, variety and food quality, all of which have solid evidence behind them. It does not work as a precise biological prescription, and anyone promising a transformed microbiome in a fortnight is overselling it. For the bigger picture on what genuinely shifts microbial variety, see our guide to increasing gut bacteria diversity.

How plant diversity changes your gut

Different fibres feed different microbes

Dietary fibre is not one substance. Inulin from chicory and onions, beta-glucan from oats and barley, pectin from apples and citrus, resistant starch from cooled potatoes and lentils, and cellulose from leafy greens are all chemically distinct. Gut bacteria carry different carbohydrate-active enzymes, so each fibre type supports a different subset of the community. This is why psyllium and inulin behave so differently in practice.

Fermentation produces short-chain fatty acids

When bacteria ferment fibre in the colon, they release short-chain fatty acids — mainly butyrate, propionate and acetate. Butyrate is the primary fuel source for colonocytes, the cells lining your large intestine. Adequate butyrate supports tight junction integrity, which is central to gut barrier function. Some people supplement directly with a butyrate supplement, though producing it from food is the more physiological route.

Polyphenols act as a second, overlooked fuel

Deeply coloured plants — berries, red cabbage, black beans, green tea, olives, cocoa — are rich in polyphenols. Most polyphenols are poorly absorbed in the small intestine and reach the colon largely intact, where microbes metabolise them into smaller bioactive compounds. This is one reason colour variety matters as much as species count.

Where fermented foods fit in

Given the Stanford findings, adding fermented foods alongside plant variety looks like the stronger combination. Live yoghurt, kefir, unpasteurised sauerkraut, kimchi and kombucha all contribute live microbes rather than just food for existing ones.

Health benefits linked to eating 30 plants a week

Bear in mind that most of the evidence below is for high fibre intake and high plant-diversity diets in general, rather than for the 30 plants challenge specifically. The distinction is important and rarely made.

Digestion and regularity

Fibre adds stool bulk and reduces transit time. The SACN review found the most consistent evidence for fibre was in bowel function. If your stools are consistently hard or infrequent, plant variety is a first-line intervention — check yours against the Bristol stool chart and read our guide to constipation relief.

Immune function

Roughly 70% of immune tissue sits in and around the gut. Short-chain fatty acids influence regulatory T-cell activity and the inflammatory tone of the gut lining. The Stanford trial's finding of reduced inflammatory markers on a microbiota-targeted diet supports this pathway. More on the gut and immune system.

Blood sugar and cholesterol

Viscous soluble fibres slow gastric emptying and glucose absorption, and bind bile acids, prompting the liver to draw on circulating cholesterol. Reynolds and colleagues found clinical trials showed lower body weight, systolic blood pressure and total cholesterol at higher fibre intakes. See fibre and cholesterol and gut health and blood sugar.

Mood and the gut-brain axis

The gut and brain communicate bidirectionally via the vagus nerve, immune signalling and microbial metabolites. Research in this area is genuinely promising but still early, and no one should expect plant variety to treat a mental health condition. Read more on the gut-brain connection and the vagus nerve.

Weight, skin and hormones

Higher fibre diets are associated with lower long-term weight gain, likely via satiety and fermentation-driven appetite signalling. Emerging work links the microbiome to skin health and hormone regulation, though these connections remain less firmly established than the digestive and cardiometabolic ones.

What counts as a plant point (and what doesn't)

There is no official scoring system — the 30 plants target is not a government guideline, and no regulator has defined the rules. What follows is the widely used convention popularised by gut health clinicians and researchers, which we've found workable in practice.

The scoring rules

Food category	Points	Examples
Vegetables	1 each	Broccoli, leek, carrot, spinach, courgette, red pepper
Fruit	1 each	Apple, blueberry, banana, orange, plum, kiwi
Wholegrains	1 each	Oats, brown rice, quinoa, barley, buckwheat, rye
Legumes and pulses	1 each	Red lentils, chickpeas, black beans, butter beans, peas
Nuts	1 each	Almonds, walnuts, cashews, hazelnuts, pistachios
Seeds	1 each	Chia, flaxseed, pumpkin, sunflower, sesame
Herbs and spices	¼ each	Cumin, turmeric, basil, coriander, cinnamon, oregano
Other plant-derived	¼ each	Coffee, tea, extra virgin olive oil, dark chocolate (70%+)

The rules that trip people up

• Count each plant once per week, no matter how often you eat it. Porridge every morning is one point for oats, not seven.
• Different varieties count separately if they're genuinely different plants: red onion and white onion, or red lentils and green lentils, count as two. Two varieties of apple generally count as one.
• Refined grains don't count. White bread, white pasta and white rice have had the fibre-rich bran and germ removed.
• Frozen and tinned count fully. Frozen peas, tinned chickpeas and tinned tomatoes are all legitimate points.
• Herbs and spices are the easiest win. Four different spices in a curry equals one full plant point for essentially no effort.
• Potatoes count towards plant points even though they don't count towards 5 A Day, because they still feed gut bacteria — particularly when cooked and cooled, which raises their resistant starch content.

How to hit 30 plants a week in the UK

A realistic UK week

This example reaches 30 without a single unusual ingredient or specialist shop.

Meal or moment	Plants	Running total
Porridge with mixed berries, flaxseed and cinnamon	Oats, blueberry, raspberry, flaxseed, cinnamon (¼)	4¼
Mixed nut and seed snack pot	Almond, walnut, pumpkin seed, sunflower seed	8¼
Lentil soup with wholemeal bread	Red lentil, carrot, celery, onion, wheat, cumin (¼)	14½
Chickpea and vegetable curry with brown rice	Chickpea, spinach, tomato, garlic, ginger (¼), turmeric (¼), coriander (¼), brown rice	21¼
Big mixed salad with lunch	Rocket, cucumber, red pepper, avocado, olive oil (¼)	25½
Roast dinner sides	Broccoli, sweet potato, leek	28½
Snacks and extras	Apple, banana, dark chocolate (¼), coffee (¼)	31

Ten swaps that add points without extra cooking

1. Buy a frozen mixed vegetable bag instead of single-vegetable bags — instantly four to six points.
2. Swap plain rice for a mixed grain pouch containing quinoa, bulgur and red rice.
3. Keep a jar of mixed seeds by the kettle and scatter on everything savoury.
4. Choose mixed frozen berries over a single fruit.
5. Use a four-bean tinned mix instead of a single tin of baked beans.
6. Add a tin of lentils to any mince-based dish — bolognese, chilli, cottage pie.
7. Switch from a single-nut pack to a mixed nut pack.
8. Buy a mixed leaf salad bag rather than a single lettuce.
9. Build a spice drawer and use three or four per dish rather than one.
10. Choose seeded or multigrain bread over plain wholemeal.

Track it, at least at first

Most people wildly overestimate their plant variety. Write your points on the back of a shopping list or in your phone notes for two weeks. Nearly everyone finds the same thing: they eat far fewer distinct plants than they assumed, and they eat the same eight or nine on repeat.

A four-week 30 plants challenge plan

Jumping from 10 plants to 30 in one week is the single most common reason people abandon the challenge. The bloating and wind that follow a sudden fibre increase are unpleasant and entirely avoidable. Build gradually.

Week 1: measure, don't change

Eat exactly as you normally would and count your plant points. This is your baseline. Most UK adults land somewhere between 8 and 15. Do not increase fibre this week.

Week 2: add five, focus on herbs and spices

Add five new plants. Choose herbs, spices and small additions like seeds, which add variety without a big fibre jump. Drink an extra glass of water daily — fibre needs fluid to work properly.

Week 3: add five more, introduce legumes

Bring in beans and lentils, but in small amounts to start: a couple of tablespoons added to an existing dish rather than a full portion. Legumes are the most common trigger for wind, and tolerance genuinely improves with gradual exposure.

Week 4: reach and hold at 30

Fill remaining gaps with fruit, wholegrains and vegetables. Once you reach 30, the real goal is consistency — a sustained 25 every week beats an occasional heroic 35.

Beyond week 4: rotate

Rotate your list seasonally rather than eating the same 30 forever. Seasonal rotation is also cheaper, since in-season produce costs less.

Doing it on a budget

Cost is the most legitimate criticism of the 30 plants challenge, and it's worth taking seriously — buying 30 different fresh plant foods weekly is not affordable for every household. These strategies bring the cost down substantially:

• Dried pulses are among the cheapest foods in any UK supermarket. A bag of red lentils costs pennies per serving and delivers a full point.
• Frozen mixed vegetables and berries are cheaper than fresh, last for months, and are nutritionally comparable or sometimes better, since they're frozen close to harvest.
• Tinned pulses and tomatoes keep indefinitely. Choose no-added-salt versions where available.
• Spices in large bags from world food aisles cost a fraction of supermarket jars.
• Buy seasonal and accept substitutions — the point is variety, not any specific plant.
• Split bulk buys with a neighbour or family member if quantities are the barrier.

Side effects, risks and who should be careful

Bloating, wind and cramping

These are the usual side effects of increasing fibre quickly, and they are almost always temporary. Fermentation of new fibre types produces gas until your microbial community adapts. Increase slowly, drink more water, and give it two to four weeks. Our guides to trapped wind relief and foods that cause bloating cover this in more detail.

If you have IBS

The 30 plants approach can be counterproductive during an active IBS flare. Many high-plant-point foods — onions, garlic, legumes, apples, wheat — are high in FODMAPs and are common symptom triggers. If you have diagnosed IBS, a structured low FODMAP diet supervised by a dietitian, followed by careful reintroduction, is usually the better sequence. Diversity comes after symptom control, not before it. See also IBS types.

If you have IBD, diverticular disease or a stricture

People with Crohn's disease, ulcerative colitis, known intestinal strictures, or those recovering from bowel surgery may need a restricted-fibre diet at certain times. Do not increase fibre substantially without speaking to your gastroenterology team or dietitian. Our guides to Crohn's diet and ulcerative colitis diet discuss this further.

If you have SIBO, coeliac disease or histamine intolerance

In small intestinal bacterial overgrowth, fermentable fibre can worsen symptoms because fermentation is happening in the wrong place. People with coeliac disease must avoid wheat, barley and rye entirely and should build variety from naturally gluten-free plants instead.

When to see a GP

No dietary challenge substitutes for medical assessment. Book an appointment promptly if you have any of the following, and do not attribute them to a change in diet:

• Blood in your stool, or black tarry stools
• Unexplained weight loss
• A persistent change in bowel habit lasting more than three weeks
• Difficulty swallowing, or persistent vomiting
• A lump or swelling in your abdomen
• Persistent abdominal pain, or symptoms that wake you at night
• Unexplained fatigue or symptoms of anaemia

Read our guidance on when to see a GP about stomach symptoms and on bowel cancer screening in the UK.

Do you still need supplements?

Food should always be the foundation. No supplement replicates the fibre, polyphenol and micronutrient complexity of 30 different plants. That said, supplements have specific, limited roles.

Probiotics

Probiotics add live organisms; plants feed the ones you already have. Given the Stanford trial's finding that fermented foods raised diversity where fibre alone did not, there's a reasonable rationale for combining approaches. Strain choice matters more than CFU count — see how to choose a probiotic, best probiotics UK, and browse the Welzo probiotics range.

Prebiotic and fibre supplements

If you struggle to reach 30 plants — because of shift work, travel, budget or appetite — a prebiotic can help bridge the gap. Citrus pectin powder supplies a soluble fibre found naturally in citrus peel and apples. Compare options in best prebiotic supplements UK and prebiotic vs probiotic.

Targeted options

Akkermansia muciniphila is a mucin-degrading bacterium of active research interest in metabolic health; see Akkermansia vs probiotics. Berberine and TUDCA are used for metabolic and bile-related support respectively — check berberine interactions before starting, particularly if you take other medication. Browse the full gut health range.

Testing

Microbiome testing is improving but remains a research-grade tool rather than a clinical one; results are difficult to act on. If you're curious, our gut microbiome test UK guide explains what these tests can and cannot tell you.

Five myths about the 30 plants challenge

Myth 1: You need to be vegetarian or vegan

You don't. The American Gut analysis found plant variety, not the absence of meat, tracked with microbiome diversity. Omnivores eating 30 plant types showed the same pattern as vegetarians.

Myth 2: Hitting 29 means you failed

The relationship is a gradient, not a threshold. Someone moving from 12 to 22 plants weekly has made a substantial change.

Myth 3: Supplements can replace the plants

No fibre supplement provides the structural diversity of 30 different plant species. Supplements complement food; they don't substitute for it.

Myth 4: You'll feel different within a week

Bowel regularity may shift within days. Microbiome composition changes take longer, and the Stanford trial suggests diversity may not shift measurably even after 10 weeks of high fibre alone. Judge it over months.

Myth 5: More is always better

Beyond a point, plant variety brings diminishing returns and, for some people with gut conditions, active harm. There's no evidence that 50 plants weekly beats 30.

Frequently asked questions

How many plants a week should I eat?

Thirty different plant foods per week is the widely used target, based on the American Gut Project's finding that people eating 30+ plant types had more diverse gut microbiomes than those eating fewer than 10. There's no evidence of a biological threshold at exactly 30 — benefits appear on a gradient, so any increase in variety is worthwhile.

What counts as a plant in the 30 plants a week challenge?

Fruit, vegetables, wholegrains, legumes, nuts and seeds each count as one point. Herbs, spices, coffee, tea, extra virgin olive oil and dark chocolate typically count as a quarter point each. Each plant counts once per week regardless of how often you eat it. Refined grains such as white bread and white rice don't count.

Does the 30 plants a week challenge actually work?

The underlying principle is well supported: greater plant variety is consistently associated with greater gut microbiome diversity, and higher fibre intake is linked to a 15–30% reduction in all-cause and cardiovascular mortality in Lancet meta-analyses. However, the original evidence is observational, and a 2021 randomised trial found that increasing fibre alone did not raise microbiome diversity over 10 weeks. It works best as a practical framework, not a precise prescription.

Do herbs and spices count towards 30 plants a week?

Yes, conventionally at a quarter point each, because you eat them in small quantities. Four different herbs or spices equal one full plant point. They're the easiest and cheapest way to add points — a single curry with cumin, turmeric, coriander and ginger scores a full point.

How long does it take to see benefits from eating 30 plants a week?

Bowel regularity often improves within one to two weeks. Bloating from the fibre increase usually settles within two to four weeks. Measurable changes to microbiome composition and inflammatory markers typically take longer — trials generally run 6 to 12 weeks, and even then results vary considerably between individuals.

Can you eat 30 plants a week on a budget?

Yes. Dried lentils, tinned pulses, frozen mixed vegetables, frozen berries, oats and bulk spices from world food aisles are among the cheapest foods in UK supermarkets and each contribute plant points. Frozen and tinned produce counts fully and is often cheaper than fresh with comparable nutritional value.

Is 30 plants a week suitable if you have IBS?

Not necessarily, and not as a first step. Many high plant point foods including onions, garlic, legumes, wheat and apples are high in FODMAPs and commonly trigger IBS symptoms. Most people with IBS do better with a structured low FODMAP elimination and reintroduction under dietetic supervision, then build variety within their tolerated foods.

Does coffee count towards 30 plants a week?

Coffee is plant-derived and is conventionally counted as a quarter point, as are tea, olive oil and dark chocolate above 70% cocoa. Coffee also contains polyphenols that reach the colon and are metabolised by gut bacteria. It shouldn't be relied on as a significant contributor, though.

What's the difference between 30 plants a week and 5 A Day?

5 A Day is about quantity — 400g of fruit and vegetables daily, based on WHO advice. The 30 plants target is about variety and counts a wider range of foods including wholegrains, legumes, nuts, seeds, herbs and spices. They're complementary rather than competing: you can meet both simultaneously, and doing so is the ideal.

Do I need to take probiotics if I eat 30 plants a week?

Not necessarily. Plants feed the bacteria you already have; probiotics introduce new ones. Some evidence suggests fermented foods raise microbiome diversity more reliably than fibre alone over short periods, so combining plant variety with live fermented foods or a probiotic is a reasonable strategy. Speak to your GP or pharmacist first if you're immunocompromised, pregnant, or taking medication.

References

1. McDonald D, Hyde E, Debelius JW, et al. American Gut: an Open Platform for Citizen Science Microbiome Research. mSystems. 2018;3(3):e00031-18.
2. The Microsetta Initiative, UC San Diego. 30 Plants Per Week: Why Eating More Fruits and Vegetables Matters for Your Gut Microbiome.
3. Reynolds A, Mann J, Cummings J, et al. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. The Lancet. 2019;393(10170):434–445.
4. Wastyk HC, Fragiadakis GK, Perelman D, et al. Gut-microbiota-targeted diets modulate human immune status. Cell. 2021;184(16):4137–4153.e14.
5. Stanford Medicine. Fermented-food diet increases microbiome diversity, decreases inflammatory proteins, study finds. 2021.
6. British Nutrition Foundation. Fibre — Nutrition Information.
7. Public Health England. National Diet and Nutrition Survey: Results from Years 7 and 8 (combined). 2018.
8. HEART UK. Fibre and wholegrain recommendations.
9. NHS. Why 5 A Day?
10. NHS. 5 A Day: what counts?
11. Valdes AM, Walter J, Segal E, Spector TD. Role of the gut microbiota in nutrition and health. BMJ. 2018;361:k2179.
12. Kelly J, Stanner S, Buttriss J, et al. Increasing fibre intake in the UK: lessons from the Danish Whole Grain Partnership. Proceedings of the Nutrition Society. 2024.
13. Science Media Centre. Expert reaction to systematic reviews and meta-analyses about dietary fibre and the risk of non-communicable disease. 2019.
14. The Conversation. The 30-plants-a-week challenge: you'll still see gut health benefits even if you don't meet this goal. 2026.

Image credits

All images are sourced from Wikimedia Commons under public domain or Creative Commons licences. No copyrighted or stock-licensed imagery is used.

• Fruits and vegetables (1) — public domain (USDA Agricultural Research Service)
• Foods (cropped) — Public Domain Mark 1.0
• Various legumes — Wikimedia Commons, see file page for licence
• 3 types of lentil — CC BY-SA
• White, Brown, Red & Wild rice — CC BY-SA 3.0, Earth100
• Spices in an Indian kitchen — Wikimedia Commons, see file page for licence
• Fruit and vegetables basket — Public Domain Mark 1.0
• Bean market — CC BY-SA 2.0, CIAT

About the author

Dr Zeeshan Afzal (MBBS) is a practising medical doctor and Clinical Content Lead at Welzo, where he writes and reviews evidence-based health content for a UK audience. He has a particular interest in digestive health, nutrition and preventative medicine.

Medical disclaimer

This article is for general information and is not a substitute for individual medical advice. It should not be used to diagnose or treat any condition. Speak to your GP, pharmacist or a registered dietitian before making significant dietary changes, particularly if you have a diagnosed gastrointestinal condition, are pregnant or breastfeeding, are taking prescribed medication, or have a history of disordered eating. If you experience blood in your stool, unexplained weight loss, or a persistent change in bowel habit lasting more than three weeks, contact your GP promptly. In an emergency, call 999 or attend your nearest A&E.

Content last reviewed 28 July 2026. Next review due July 2027.