Your Greek yogurt for breakfast, quinoa and veggie bowls for lunch, and salmon for dinner routine makes clean eating crazy easy. The macros and calories are already figured out, so you don’t have to bust out a calculator every time you sit down for a meal. And since these foods are all satisfying but not exactly exciting, there’s no real temptation to overeat.
It’s a good groove, except for this: Your boring healthy diet might be making it harder to lose weight. Turns out, chowing down on a variety of good-for-you stuff can play an important role in promoting greater bacterial diversity in your gut. And that diversity might be key to keeping your weight in check—plus avoiding more serious health issues like diabetes, according to research presented last month at the Institute of Food Technologists’ annual meeting.
“Each type of food and micronutrient seems to have a [bacterial] specialist that can utilize it. So maybe the best diet has a little bit of everything,” says Mark Heiman, vice president and chief scientific officer at Microbiome Therapeutics.
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Which, when you think about it, makes a lot of sense. Remember that whole thing about survival of the fittest? It doesn’t just apply to animals living in the jungle. If you load up on eggs and spinach every single day and never eat, say, oatmeal and blueberries, then the bugs that favor using the nutrients from eggs and spinach are gonna have a leg up over the ones that favor using the nutrients from oatmeal and blueberries. Eventually, they might wipe out the oatmeal-and-blueberry-loving bacteria altogether.
That’s bad news, since different types of bacteria work to produce different components of our physiology, explains Heiman. Some, for instance, might play a role in hunger and fullness, or blood sugar control, or inflammation.
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Experts still have tons to learn about how various strains of gut bacteria affect our health—and how eating certain foods encourages the growth of certain bugs over others. Still, you’ll likely only benefit from mixing things up. In addition to fostering a bacterial melting pot in your belly, you’ll get a wider range of important vitamins, minerals, and antioxidants. Which, of course, is always a good thing. (Hack your gut bacteria for easier-than-ever weight loss with The Good Gut Diet.)
In practice, that might mean throwing a different type of berry into your smoothie each morning, or alternating between different types of veggies instead of doing just cauliflower or broccoli with dinner. But it’s also about not going too extreme with your ratio of protein, carbs, and fat. “If you don’t eat any carbs, the bacteria that specialize in using carbs will be at a disadvantage, while the guys who specialize in using protein will become more abundant, so your [microbial] ecosystem becomes less diverse,” Heiman says. Permission to pick the sandwich over the salad once in a while? Granted.