What is the 30 Foods Challenge and Why Does It Boost Gut Health?

December 12, 2025 •

4 min read

According to the American Gut Project, people who ate 30 or more different plant-based foods per week had a more diverse gut microbiome than those who ate 10 or fewer. This scientific finding is the very foundation of the popular 30 Foods Challenge, a dietary goal that has gained significant traction for its emphasis on diversity over quantity.

Quick Summary

The 30 Foods Challenge encourages participants to consume 30 different plant-based foods per week to enhance gut microbiome diversity. This practice is based on research linking a wide variety of fibrous plants, legumes, nuts, seeds, herbs, and spices to improved digestive and overall health.

Key Points

Boosts Gut Microbiome Diversity: The challenge is founded on research from the American Gut Project, which showed that eating 30+ different plants weekly leads to a healthier and more diverse range of gut bacteria.
Emphasizes Variety, Not Quantity: The goal is to eat 30 different types of plants, not larger portions. Fruits, vegetables, nuts, seeds, legumes, and whole grains all count.
Improves Digestion and Immunity: A diverse gut microbiome supports better digestive function, nutrient absorption, and strengthens the immune system against pathogens.
Easy to Implement: Simple tips like adding seeds to oatmeal, using different herbs, and varying your side dishes can help you reach the goal without major dietary changes.
Promotes Sustainable Healthy Habits: Unlike restrictive diets, the challenge encourages lifelong habits of mindful, varied eating that can lead to long-term health benefits, including better mood and energy.
Broadens Food Horizons: The challenge encourages you to discover and incorporate new foods, making mealtimes more exciting and preventing food ruts.

What is the 30 Foods Challenge?

At its core, the 30 Foods Challenge is a dietary goal to consume at least 30 different plant-based foods within a single week. Unlike restrictive diets that focus on elimination, this challenge promotes inclusion and variety. The 'foods' include a broad range of plant types, encompassing more than just fruits and vegetables. The ultimate aim is to increase the diversity of the gut microbiome, the collection of trillions of microbes living in your digestive tract. This diversity is crucial for a robust immune system, better digestion, and improved overall health.

Where Did the Number 30 Come From?

This concept gained prominence largely due to the American Gut Project, one of the largest studies of the human microbiome. Researchers found a significant correlation between the number of different plants consumed weekly and the diversity of gut bacteria. The study showed that participants eating 30 or more plant varieties had a significantly more diverse and healthier gut microbiome compared to those eating 10 or fewer. The number 30 became the tipping point for observable health benefits.

What Counts as a 'Food' in the Challenge?

For the purpose of this challenge, a 'food' is any distinct type of plant you consume within the seven-day period. This includes but is not limited to:

Fruits: Apples, bananas, berries, citrus fruits, and tomatoes.
Vegetables: Leafy greens, root vegetables, cruciferous vegetables, and nightshades. Different colored versions of the same vegetable, like red and yellow bell peppers, can even count as separate items.
Legumes: Beans, lentils, chickpeas, and peas.
Whole Grains: Oats, brown rice, quinoa, and barley.
Nuts and Seeds: Walnuts, almonds, chia seeds, and pumpkin seeds.
Herbs and Spices: Basil, oregano, cinnamon, turmeric, and black pepper. Many challenges count these as a fraction of a point, but their inclusion is still encouraged for variety.
Other Plant-Based Items: Items like coffee, tea, and dark chocolate can also be counted.

The Health Benefits of the 30 Foods Challenge

Boosting the diversity of your plant food intake can have a cascade of positive effects on your health. The varied fibers, polyphenols, and other nutrients feed a wider range of beneficial gut bacteria.

Improved Digestion

Feeding a diverse set of gut microbes can lead to improved digestive function. Different bacteria break down different types of fiber and produce beneficial compounds, like short-chain fatty acids, which nourish the colon and improve gut health. This can help with issues such as bloating and irregular bowel movements.

Enhanced Immune Function

A diverse gut microbiome is strongly associated with a more robust and resilient immune system. By regularly consuming a variety of plant foods, you strengthen the army of beneficial bacteria that help protect your body from pathogens and reduce inflammation.

Potential Mood and Energy Improvements

There is a strong connection between gut health and mental well-being, often referred to as the gut-brain axis. Increased microbiome diversity can lead to enhanced mood and more stable energy levels. This is partly because a healthier gut can lead to better nutrient absorption and reduced inflammation, which impacts neurological functions.

Practical Tips for Succeeding in the Challenge

Reaching 30 different plant foods in a week is easier than it sounds. It requires mindful choices and a willingness to step outside of your usual routine. Here are some strategies:

Start with Breakfast: Add seeds (chia, flax), mixed berries, and nuts to your oatmeal or yogurt. One meal can quickly accumulate 3-5 points.
Supercharge Your Salads: A lunchtime salad is an easy way to pack in variety. Use mixed greens, add different colored vegetables, toss in chickpeas or lentils, and top with a sprinkle of different seeds.
Embrace Soups and Stews: Batch-cook a large pot of vegetable or lentil soup. Use a medley of different root vegetables, greens, and spices to rack up points effortlessly.
Change Up Your Grains: Instead of always using white rice, alternate with quinoa, barley, or bulgur wheat. Different grains offer different benefits and count as distinct foods.
Use Herbs and Spices Liberally: Don't underestimate the power of a flavor boost. Add fresh or dried herbs to your cooking, and don't be afraid to experiment with different spices like turmeric, paprika, and cumin.
Snack Smart: Swap processed snacks for healthier options like mixed nuts, veggie sticks with hummus, or different types of fruit.

Tracking Your Progress

Keeping track is key to staying motivated. A simple method is to create a weekly checklist or use a mobile app to log each new plant food you consume. Each food counts only once per week, so a banana eaten on Monday and again on Wednesday still only counts as one point.


Food Category	Examples	Easy Ways to Add
Vegetables	Broccoli, carrots, kale, bell peppers, sweet potatoes, onions	Soups, stews, salads, stir-fries, roasted vegetables
Fruits	Apples, bananas, mixed berries, oranges, avocado, kiwi	Smoothies, yogurt toppings, snacks, desserts
Legumes	Lentils, chickpeas, black beans, kidney beans, edamame	Salads, stews, dips (hummus), vegetarian chilis
Whole Grains	Oats, quinoa, barley, farro, brown rice	Porridge, side dishes, soups, grain bowls
Nuts & Seeds	Almonds, walnuts, chia seeds, flax seeds, pumpkin seeds	Toppings for yogurt/cereal, added to smoothies, baked goods
Herbs & Spices	Basil, oregano, turmeric, cinnamon, ginger, pepper	Sauces, marinades, dressings, seasoning for any meal

Conclusion

The 30 Foods Challenge is more than just a passing trend; it's a scientifically-backed approach to improving your health by focusing on dietary variety. By consciously expanding your range of plant-based foods, you can significantly enhance the diversity of your gut microbiome, leading to benefits for digestion, immunity, and overall well-being. This inclusive eating pattern is a sustainable and enjoyable way to cultivate healthier, more mindful eating habits for the long term. Start small, track your progress, and you'll be amazed at how quickly the numbers add up.

One helpful resource for exploring the origins of this challenge and its connection to gut health is the ZOE website, which features content from researcher Professor Tim Spector, who popularized the concept in the UK. Find more information here: Eating 30 Plants per Week: How To Do It and Why.

Frequently Asked Questions

The 30 Foods Challenge is a weekly dietary objective to consume at least 30 distinct types of plant-based foods. The goal is to promote a wider variety of plants in your diet to support a healthier, more diverse gut microbiome, rather than focusing on calorie restriction or specific portion sizes.

No, quantity is not the focus of this challenge, and portions do not matter. The goal is to consume a variety of different plant foods, not large quantities of each. Even a small amount of a specific plant food, like a sprinkle of seeds or a pinch of an herb, counts as one item for the week.

Foods that count include fruits, vegetables, whole grains, legumes, nuts, seeds, and even herbs and spices. Different colors of the same vegetable, like red and yellow bell peppers, also count as separate foods.

Yes, herbs and spices count towards your total, though some variations of the challenge assign them fractional points due to smaller serving sizes. They are an excellent, low-effort way to boost your plant variety.

While the focus of the challenge is heavily on plant-based foods due to their direct impact on gut microbiome diversity, you do not have to be completely plant-based. The challenge is meant to increase the variety of plants in your diet, not eliminate other food groups.

The main benefits include improved gut health, a more diverse and resilient gut microbiome, better digestion, a stronger immune system, and potential improvements in mood and energy levels.

The simplest method is to use a checklist, journal, or app to track each new plant food as you consume it. A food only counts once per week, no matter how many times you eat it.