One popular approach is the “30 plants a week” goal: eating at least 30 different types of plant foods over the course of seven days. The idea isn't that 30 is a magical number. Instead, it encourages people to move beyond eating the same handful of fruits and vegetables every week and introduce greater variety into their diets.
Your digestive tract is home to a complex community of microorganisms, collectively known as the gut microbiome. Different microbes thrive on different components of the foods we eat.
Plant foods contain a wide variety of dietary fibers, resistant starches, polyphenols, and other compounds that interact with the microbiome. Eating a broader range of plants potentially provides a wider selection of nutrients and substrates for different microbial populations.
Research involving large groups of people has found associations between greater dietary plant diversity and measures of gut microbial diversity. Importantly, however, researchers are still studying exactly how microbiome diversity relates to long-term health. A diverse microbiome isn't a guarantee of good health, and there's no single "perfect" microbiome shared by everyone.
The beauty of the 30-plants-a-week concept is that the definition can be surprisingly broad. You don't have to eat 30 different vegetables. Count fruits, vegetables, legumes, whole grains, nuts, seeds, herbs, and spices.
For example, breakfast might include oats, blueberries, chia seeds, and walnuts. A lunch salad could contribute spinach, tomatoes, carrots, chickpeas, and pumpkin seeds. Dinner might include broccoli, brown rice, garlic, onions, and lentils.
Herbs and spices can help, too. Parsley, basil, cinnamon, turmeric, ginger, oregano, and other plant ingredients add variety even when they're used in relatively small amounts. The goal isn't to obsessively count every plant or force yourself to eat foods you dislike. Instead, use the number as a weekly challenge to expand your menu.
If you normally eat apples, bananas, and carrots, try adding pears, berries, cabbage, lentils, beans, mushrooms, different leafy greens, nuts, and seeds. Frozen and canned produce can also make variety easier and more affordable. Whole grains such as oats, barley, quinoa, and whole-grain breads provide additional opportunities to diversify.
This approach doesn't mean probiotics are useless or that fermented foods should be abandoned. Foods such as yogurt, kefir, kimchi, sauerkraut, and other fermented products can be part of a healthy eating pattern. But a probiotic supplement typically contains a limited number of microbial strains. Plant diversity takes a different approach: feeding the microbes already living in your gut with a wide variety of compounds.
The bigger lesson is simple: instead of asking only, “Which probiotic should I take?” consider asking, “How many different plants did I eat this week?” Thirty isn't a magic number, but it can be a useful reminder that when it comes to gut health, variety may be one of the most practical ingredients on the menu.