loamWhere the number comes from
The 30-plants target traces to the 2018 American Gut Project — a citizen-science study of 10,000+ people across the US, UK and Australia — and was popularised by Prof. Tim Spector, co-founder of ZOE. People who ate 30+ different plants a week had a more diverse gut microbiome than those who ate fewer than 10.
Important nuance. This is an association, not proof of cause — and researchers note you still see benefits even if you don't hit exactly 30. It's a direction, not a pass/fail.
What counts as a plant?
Any distinct plant food counts once per week. There are six families to draw from: fruit, vegetables, legumes (beans, lentils, peas), whole grains, nuts & seeds, and herbs & spices. Different plants bring different fibers and polyphenols, which is the whole point — diversity feeds a wider range of microbes.
Practical rules.
- Herbs and spices count — they're smaller wins, but they still count.
- A mix of colours counts extra (more on that below).
- Different varieties of the same plant — say, two types of apple — count once, not twice.
- Refined foods like white bread or oil don't count; the plant needs to still resemble itself.
Eat the rainbow
Different pigments feed different microbes, so it helps to think in colour as well as in count. Aim for several of these groups across your week:
- Red & pink — tomato, raspberry
- Purple & blue — blueberry, red cabbage
- Orange & yellow — carrot, mango
- Green — spinach, broccoli
- White & brown — garlic, oats, mushrooms
An easy way to actually hit 30
You don't need a spreadsheet — a few small habits get most people there.
- Build meals around legumes and whole grains. A bean-and-grain base can quietly bring 3–4 plants to a single plate.
- Add a handful of nuts or seeds. A small daily handful counts, and mixing up which ones you reach for adds variety fast.
- Keep frozen mixed veg and berries on hand. Frozen counts the same as fresh, and a mixed bag can be 5+ plants in one scoop.
- Sprinkle in herbs and spices. Basil, turmeric, cumin, chili flakes — easy, low-effort additions to the count.
- Track it. The only way to know you're at 16 and not 30 is to see the number — which is where most of the gap quietly hides.
Count every plant, automatically
loam counts your distinct plants Monday to Sunday across all six families, and shows a live "16 / 30 this week" ring so you always know where you stand. It breaks your week into the five plant-colour groups above, and suggests "plants you haven't tried this week" so you always know your next easy win. Free, no account, private by design.
Download loam on the App Store →Frequently asked
What counts as a plant for the 30-a-week goal?
Any distinct plant food, counted once per week, across six families: fruit, vegetables, legumes (beans, lentils, peas), whole grains, nuts & seeds, and herbs & spices. Different varieties of the same plant — like two types of apple — only count once, and refined foods like white bread or oil don't count.
Do herbs and spices really count?
Yes — they count as smaller wins toward your 30. They're less bulky than a serving of vegetables, but they still bring their own fibers and polyphenols, so a sprinkle of turmeric or a handful of basil genuinely adds to your weekly variety.
Is 30 a magic number?
No — it's a memorable target from the research, not a strict pass/fail line. More plant variety is better, and studies suggest you still see gut-health benefits even if you land at 20 or 25 rather than exactly 30.
Sources: 2018 American Gut Project (McDonald et al., mSystems); popularised by Prof. Tim Spector and ZOE; The Conversation on partial-progress benefits. loam supports general wellness and education — it is not medical advice.