Will Bulsiewicz, MD, MSCI, a Charleston-based gut health expert, underwent a major lifestyle change after 16 years of rigorous training to become a gastroenterologist. He says he “came out on the other side” of residency with a slew of chronic health problems and wanted a real solution beyond pills and procedures. Endless hours of research launched Dr. Bulsiewicz into what he calls a “plant-predominate” diet that completely transformed his health, and soon became the foundation of his medical practice. He is now the author of two books: Fiber Fueled, and the upcoming Fiber Fueled: The Cookbook, and has amassed an impressive Instagram following from people around the world seeking answers to their gut health questions and solutions for (all-too-common) digestive woes.

“We often over-emphasize the importance of bowel movement frequency, because having good digestive health is about so much more than that,” Dr. Bulsiewicz says. “Regularity should just mean that a person is ‘in rhythm’ at a cadence that is normal for them. When a bowel movement happens, it should be complete—which is an important word for me as a GI doctor—effortless, and dare I say, satisfying.”

Dr. Bulsiewicz says a person could think they are regular because they have a daily bowel movement (or even multiple), but a person can still be constipated if their bowel movements aren’t complete or effortless. While fiber and nutrition aren’t the only solutions to achieving better bowel movements, he says they are good places to start for building a healthier gut and encouraging regularity. “We know that at least 95 percent of Americans are inadequate in their fiber consumption,” says Dr. Bulsiewicz. “My philosophy is more than just about eating more plants. What my whole philosophy is focused on is eating as many colors and as much variety in meals as possible.”

Dr. Bulsiewicz says that though it’s imperative to keep fiber in mind when trying to maintain a well-balanced microbiome—especially when so few Americans are getting enough—that isn’t the only nutrient or factor at play. “Our modern lifestyles that have us stressed and lacking movement, the preservatives and other chemicals in highly-processed foods, and even our over-sanitized society can also contribute to poor digestive health,” he says. Keeping in mind that changing your diet is not an automatic way to finally find harmony with your digestive system, we asked Dr. Bulsiewicz to share what he eats in a day to stay regular, avoid constipation, and maintain the most optimal gut health—and overall health—of his life.

What a gastroenterologist eats for healthy digestion

First things first: coffee

“I always wake up in the morning with a big cup of coffee,” says Dr. Bulsiewicz. “Studies show that coffee changes the gut microbiome for the better and has a prebiotic benefit for the gut.” While this, he reminds, isn’t exactly an excuse to start pouring yourself mug after mug all day (caffeine is a diuretic after all), we love that coffee can be a beneficial part of our daily diets and help promote digestive health. The Mayo Clinic advises staying under 400 milligrams (mg) of caffeine a day, which is about four cups of coffee, so just keep that in mind as you sip your cold brews throughout the day—and don’t forget to stay hydrated along the way for ultimate gut-boosting benefits.

Breakfast: smoothie

More often than not, Bulsiewicz and his family start the day with hearty homemade smoothies. He says smoothies are a great gut-friendly breakfast because they taste great, are easy to drink, and have a variety of plants—he aims for five to 10 different plant foods in his smoothies—plus protein in them. Dr. Bulsiewicz adds that smoothies are an effective way to nourish your gut microbes first thing in the morning, too.

Dr. Bulsiewicz likes to keep a standard smoothie base of greens, some fruit, seeds like flax or hemp, and a healthy liquid to get a variety of nutrient-dense plant-based ingredients that will keep him energized until lunch. Adding a spoonful of nut butter or protein powder—or turning it into a smoothie bowl with a generous sprinkle of granola—can also help ensure you stay powered through the morning.

Try this delicious coconut smoothie bowl, which is packed with digestive benefits:

If you’re not a smoothie person, Dr. Bulsiewicz is also a huge fan of eating whole grains for a gut-friendly breakfast. His favorite form is oatmeal, which he tops with mixed berries, seeds, nut butter, coconut milk, and cinnamon. “Serve it with a side of kiwi, as research shows that eating two kiwis a day can improve your bowel movements,” Dr. Bulsiewicz adds.

Lunch: salad

Lunch is Dr. Bulsiewicz’s favorite time of day to clear the fridge and get experimental. He says that there’s no need to overcomplicate building a “perfect salad recipe” and to just work with what you have. (Less stress, less waste, and more variety of flavors = win.) “It may seem kind of bizarre to introduce a lot of variety in a salad bowl, but you’ll find compliments among flavors and textures that you may not have expected to enjoy so much,” Dr. Bulsiewicz says. “It’s always so interesting to get to discover with your palate during a meal.”

Dr. Bulsiewicz prefers making a salad in a mixing bowl instead of in everyday dishware to make sure everything can be properly mixed and so he doesn’t have to be limited by space. He starts with a mix of greens—spinach and arugula are almost always in the mix—and will add whatever fresh veggies and herbs he had on hand, plus a protein, and one or two types of healthy fats (he loves walnuts for extra crunch and avocado for creaminess). Finally, Dr. Bulsiewicz keeps his salad dressing simple with some extra-virgin olive oil and balsamic vinegar.

If you don’t feel like your salads fill you up enough or you want some variety in the week, try making a veggie-packed wrap, a bowl of minestrone with beans and whole grains, or make a side salad to go with your lunch. Salad doesn’t have to be the star of the show—it just serves as a simple way to get in a ton of fiber, magnesium, and other essential nutrients that keep your digestive tract humming.

Throughout the day: fermented foods

Dr. Bulsiewicz is a big believer in fermented foods—he even wrote a whole section of his new cookbook on them. Sourdough bread is one of his favorites, but he also leans into foods like kimchi and sauerkraut that are simple additions to his lunch salads and make for easy, gut-friendly garnishes for other meals. “Kombucha, yogurt, and pickled veggies can all be great additions to your diet if you’re seeking digestive regularity, too,” Dr. Bulsiewicz says.

Dinnertime: legumes and whole grains

Dr. Bulsiewicz loves a grain bowl, and he’s a particular fan of any dish that combines beans and whole grains as a foundation. Some favorites are Thai and Indian curries and burrito bowls loaded with polyphenol-rich herbs and spices.

“The backbone of the healthiest diets in the world are whole grains and legumes,” says Dr. Bulsiewicz. “I love farro, and if I’m doing a burrito bowl, I’ll pair it with black beans, guacamole, and salsa. It just needs to be filling, energizing, and delicious.”

While beans and grains do make an excellent pairing, you can always enjoy some roasted chickpeas on your salad at lunch and lean on a whole-grain, bean or lentil-based pasta at dinnertime with a veggie-packed bolognese. Another time-saving option would be to make a hearty grain salad for lunch and serve any leftover grains with miso-glazed salmon and edamame at dinner.

Now that you’ve got the gastro’s guide to gut health down pat, find a dietitian’s must-know intel on it here:

—reviewed by Jennifer Gilbert, MD, MPH

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