How (and why) to eat 30 plants a week

We’re all familiar with the five-a-day rule. It refers, of course, to the number of recommended 80g servings of fruit and vegetables you should consume daily for optimum health. But growing numbers of nutritional experts now believe there’s a better target to aim for when it comes to eating enough of the good stuff.

They’re recommending we try to eat 30 different plant foods each week in order to keep our gut microbiome in tip-top shape. That’s the complex system of trillions of microbes in our gut that profoundly influence our physical and mental health.

The magic number 30 stems from a 2018 study by the American Gut Project (initiated by scientists at the University of California San Diego), which also involved participants from Australia, the UK and 42 other countries.

“By looking at the microbiomes of tens of thousands of volunteers, we saw that people who eat around 30 different plants every week have much greater microbial diversity than those who eat just 10,” says Professor Tim Spector, a nutrition expert at King’s College London, who was involved in the study (with the British Gut Project). “Conducting this research has totally changed the way I approach my diet and, in turn, my health,” he says.

But hold on: most people in Britain can’t manage to eat their five-a-day, so isn’t 30 way too ambitious? Prof Spector says no: “It’s not as hard as you think, when you realise plant foods include nuts, seeds, grains, herbs and spices, as well as the more obvious fruit and veg.”

What are the benefits of eating 30 plants a week?

It’s now widely accepted that the greater the diversity of microbes in our gut, the better it is for our overall health. Of course, gut diversity is affected by many lifestyle factors: our genes, our environment, the amount of sleep we get and our age are among the things that play a part. But what we eat obviously has a significant influence on our gut health, too. It’s thought fibre probably plays an important role in this. Eating a wide range of plant foods – many of which are rich in fibre – can help to create the ideal nourishing environment for lots of good bugs to flourish in our gut.

The problem is, many of us reach for the same fruit and veg on repeat, says Jennifer Medhurst, registered nutritionist and author of book The Imperfect Nutritionist (Kyle Books £25), a down-to-earth nutrition guide and cookbook.

“Overall health is determined by the diversity of our gut microbiome, and our gut needs lots of different types of fibre to flourish,” she says. “You’re only going to have all these types of fibre if you’re consuming lots of different types of plant foods.” By doing this, you not only keep your digestive system in good shape but also maximise your chances of maintaining all-round good health.

“Seventy per cent of your immune system is in the gut, so improving your gut microbiome will help improve immunity, as well as a whole host of other things,” Medhurst says. “You’re more likely to bounce back from unhealthy fluctuations in your diet and be able to withstand the environmental and biological challenges of daily life.”

How to eat 30 plants a week

‘Eating the rainbow’ is a fantastic way to nudge your tally higher, says Medhurst: “One of the first things I do with my clients is ask them to try to include five different colours of fruit and vegetables in their diet each day. This not only helps them reach their five-a-day – ideally we should eat seven to 10 a day, actually – but also improves the diversity of what you’re eating.”

It’s undeniable that eating a varied diet, including a wide range of plant foods, is good for you. But while some people will enjoy the challenge of hitting the 30-a-week target, others will find it difficult, for a range of reasons. It’s important not to get stressed about it, Medhurst says.

Some experts suggest counting your weekly tally using a system where you aim for 30 points: one portion of a plant food counts for 1 point, and herbs and spices count for 1⁄4 point each.

If this method works for you, that’s great, but Medhurst says increasing the variety of plant foods by any amount can be beneficial, and you might find it easier to do it gradually. “It’s important not to get bogged down in counting foods,” she says. “Good health is determined by overall dietary pattern as opposed to what is done at one meal or on one day.”

The bottom line

Some nutritional experts now recommend trying to eat 30 different kinds of plant foods every week, based on research suggesting this approach can improve the diversity of our gut microbes – and, therefore, our overall physical and mental health.

As long as you eat a variety of fruit, vegetables, beans, pulses, nuts, seeds and grains, as well as a wide range within these groups, the goal should be relatively easy to achieve. But it’s important not to become obsessive about the counting… Just thinking about the variety in your diet is a good first step, and any improvement will be beneficial.

Jennifer Medhurst’s tips for eating 30 plants a week

• Eat the rainbow. Make sure you have every colour of fruit and veg possible in your shopping trolley – frozen and tinned are fine, too, as well as often being cheaper than fresh. Have at least three colours on your plate.
• Leave out a jar of mixed seeds. If you have them on hand in the kitchen it will remind you to add them to your food – they’re a great addition to salads, soups and breakfast cereal.
• Buy pre-mixed fruit & veg combos. That includes nuts, seeds, pulses, beans, ready-prepped stir-fry mixes and spice/herb mixes so you get variety in just one serving.
• Keep your herbs and spices out. As with mixed seeds, if you keep a range of dried herbs and spices within easy reach you’re more likely to experiment and add different things to different dishes. For example, cinnamon on porridge or mixed herbs in salad dressing.
• Try one new recipe each week to bring more variety to your diet.
• Experiment with eating more wholegrains. Swap rice with quinoa, for example, oats for shop-bought cereal, or try adding spelt or barley into soups or salads.

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