How Many Plant-Based Foods Should I Eat for Optimal Health?

December 25, 2025 •

4 min read

According to the American Gut Project, people who ate 30 or more different plant foods per week had a more diverse gut microbiome compared to those who ate 10 or fewer. This discovery challenges the old 'five-a-day' mantra and emphasizes the importance of variety over sheer quantity when determining how many plant-based foods to eat for optimal health.

Quick Summary

This guide outlines why dietary diversity, particularly including a wide range of plant-based foods, is a critical goal for wellness. It explores the science behind the '30 plants a week' target, what counts toward this goal, and practical strategies for incorporating more variety into your meals. Focus on whole grains, legumes, nuts, seeds, herbs, and spices to improve your intake and nourish your body.

Key Points

Variety Over Quantity: Aiming for a high number of different plant-based foods each week is more beneficial for your gut than eating large amounts of a few types.
The '30 Plants a Week' Goal: Research from the American Gut Project suggests that consuming 30 or more different plant types weekly leads to a more diverse and healthy gut microbiome.
Diverse Intake Boosts Gut Health: Different plant fibers and polyphenols feed various beneficial gut bacteria, leading to a more resilient microbial community.
Broad Definition of 'Plant Food': Your weekly count includes not just fruits and vegetables, but also nuts, seeds, legumes, whole grains, herbs, and spices.
Start with Small Changes: Incorporate more diversity by making simple swaps, adding nuts/seeds to meals, or trying a new herb or spice each week.
Focus on Whole Foods: Prioritize whole, minimally processed plant foods and limit processed vegan-friendly items, which can be high in added sugars, salt, and unhealthy fats.

The Shift from Quantity to Variety

For decades, the public health message around plant-based eating was focused on the 'five-a-day' rule for fruits and vegetables. While this advice remains a solid foundation, new research highlights that variety is arguably more important than sheer volume. Your gut microbiome thrives on diversity, and the wider the range of plants you consume, the better you feed the trillions of beneficial microorganisms living in your intestinal tract. This concept, sometimes called the 'Diversity Diet', is supported by significant findings from the American Gut Project.

The Science Behind the '30 Plants a Week' Target

In 2018, the American Gut Project published findings from a study involving thousands of participants. Researchers found a clear correlation between the number of different plant types eaten weekly and the diversity of an individual's gut microbiome. Those who consumed 30 or more different plant types weekly had a significantly more diverse microbiome than those who ate 10 or fewer. A diverse gut microbiome is linked to numerous health benefits, including a stronger immune system, lower inflammation, and better metabolic function. Different plants contain unique types of fiber (prebiotics) and plant chemicals (polyphenols) that feed different types of gut bacteria. By eating a wide variety, you are cultivating a more robust and resilient microbial community.

What Counts Toward Your 30 Plants?

Reaching 30 different plants a week may sound intimidating, but it is easier than you think once you understand what to include. A wide range of plant-based foods contributes, and each distinct item counts just once per week.

Vegetables: All vegetables count, including leafy greens (spinach, kale), cruciferous vegetables (broccoli, cauliflower), alliums (onions, garlic), and even starchy options like sweet potatoes.
Fruits: A variety of fresh, frozen, or dried fruits, such as berries, apples, bananas, and avocados, contribute to your total.
Whole Grains: Whole grains are excellent sources of fiber. Examples include oats, quinoa, brown rice, barley, and whole wheat.
Legumes: Beans, lentils, and peas are packed with fiber and protein. Varieties like chickpeas, black beans, red lentils, and kidney beans are great additions.
Nuts and Seeds: These offer healthy fats and additional fiber. Think almonds, walnuts, chia seeds, flaxseeds, and sunflower seeds.
Herbs and Spices: Don't forget these flavor-enhancers! Fresh and dried herbs like basil, oregano, parsley, and spices such as turmeric, cumin, and cinnamon all count. A small amount can add significant diversity.
Other: Fermented foods like kimchi and sauerkraut, coffee, and even dark chocolate (at least 70% cocoa) can contribute to your count.

Practical Strategies for Increasing Plant Diversity

Incorporating more plant diversity doesn't require a complete dietary overhaul. Small, consistent changes can make a big impact over time.

Start with Your Staples: Choose whole grains over refined grains. For instance, swap white rice for brown rice, or regular pasta for whole wheat or chickpea pasta.
Make Easy Swaps: Substitute a familiar item with a different plant. Use lentils instead of ground beef in bolognese or tacos. Try black bean burgers instead of beef patties.
Boost Your Bowls: For dishes like salads, soups, or Buddha bowls, add extra variety. Throw in a few different types of beans, a handful of mixed nuts and seeds, and a sprinkle of fresh herbs.
Embrace Mixed Ingredients: Look for products that naturally contain a variety of plants, such as multi-bean soup mixes or frozen vegetable medleys.
Snack Smart: Replace processed snacks with whole plant-based options. Try a piece of fruit, a handful of mixed nuts, or hummus with various veggie sticks.

Comparison Table: Quantity vs. Variety Approach


Feature	Traditional '5-a-Day' Approach (Quantity)	'30 Plants a Week' Approach (Variety)
Primary Goal	Meet a daily minimum number of fruit and vegetable servings.	Achieve a high diversity of plant types throughout the week.
Focus	Specific number of portions (e.g., 5-7 portions of fruit and veg per day).	Range of different plant species (e.g., up to 30 unique plants/week).
Gut Health Impact	Provides fiber, but may not sufficiently diversify the gut microbiome.	Actively cultivates a more diverse and resilient gut microbiome.
Dietary Scope	Primarily fruits and vegetables.	Broadens to include whole grains, legumes, nuts, seeds, herbs, and spices.
Example	Eating an apple and a portion of broccoli every day.	Eating an apple once, and trying nuts, seeds, and spices like cumin and cinnamon throughout the week.
Best Practice	Serves as a solid foundation for overall health.	Enhances general health benefits by focusing on microbial diversity.

Conclusion

While meeting a daily quota of fruits and vegetables is beneficial, a more holistic and effective approach to plant-based eating centers on maximizing variety. The '30 different plants a week' goal, inspired by the American Gut Project, provides a tangible and evidence-based target for boosting the diversity of your gut microbiome. By focusing on expanding your palate to include different types of whole grains, legumes, nuts, seeds, herbs, and spices, you are providing your body with the wide array of fibers and polyphenols it needs to thrive. This emphasis on diversity over quantity is a manageable and sustainable way to improve not just your gut health, but your overall well-being. Making small, conscious choices to vary your food intake is the key to unlocking these profound health benefits.

The Plant-Based Health Professionals UK is an organization that advocates for evidence-based plant-based nutrition for health.

Frequently Asked Questions

A plant-based diet focuses on making plants the majority of your food intake, but it doesn't always require eliminating meat entirely. Many approaches, such as flexitarianism, involve eating mostly plants while occasionally including meat.

Yes, different colored plants are associated with different phytochemicals and nutrients. Eating a 'rainbow' of fruits and vegetables helps ensure a wide range of antioxidants and health-boosting compounds.

Any increase in plant diversity is beneficial for your gut health. Don't feel discouraged if you can't reach 30 immediately; starting with 15 or 20 and gradually increasing your variety is a great goal.

For those on a fully vegan diet, fortified foods like plant-based milks and cereals are often necessary to ensure adequate intake of certain nutrients, most notably Vitamin B12, which is primarily found in animal products.

While processed plant foods might technically come from plants, focusing on whole, minimally processed options is best for nutrient density. Processed vegan foods often contain high levels of salt, sugar, and fat.

Herbs and spices are potent plant sources of polyphenols and other beneficial compounds. Each distinct herb or spice used in a week can count as a single point, providing an easy way to boost diversity.

A great first step is to focus on one meal per day or week. Try adding an extra vegetable to dinner, swapping a meat protein for a legume, or including a mix of nuts and seeds in your breakfast.