"The gastroenterologist making the case for plant diversity over any single superfood."
Will Bulsiewicz is a gastroenterologist and the author of Fiber Fueled, a book making the case that dietary fiber and plant diversity, not any single 'superfood,' are the key drivers of gut health and overall wellbeing. Bulsiewicz's central argument centers on the gut microbiome — the trillions of bacteria living in the digestive tract — and the idea that these microbes thrive on a wide variety of plant fibers, producing beneficial compounds that support immune function, reduce inflammation, and influence everything from mood to metabolic health. He's especially critical of low-carb and low-fiber diet trends, arguing that starving the microbiome of diverse plant fiber undermines long-term health even when it produces short-term weight loss. Bulsiewicz's practical recommendation is deceptively simple: eat a wide variety of plants — the more different types, the better — rather than focusing on any one 'superfood' or restrictive eating pattern.
Our in-depth summaries and reviews of his work
Fiber Fueled by Will Bulsiewicz is a science-backed guide to gut health showing why plant diversity and the F-GOALS framework can transform…
Read Summary →Bulsiewicz argues that gut bacteria thrive on a wide variety of plant fibers, and that eating many different plants matters more than focusing on any single 'superfood.'
Bulsiewicz is critical of low-carb, low-fiber diet trends, arguing they may produce short-term weight loss while starving the microbiome of the diversity it needs for long-term health.
Bulsiewicz connects gut microbiome health to immune function, inflammation, and even mood, framing fiber intake as a lever with effects well beyond digestion alone.
"Aim to eat 30 different plants each week — diversity is the single biggest lever for a healthy gut microbiome."— Fiber Fueled
"Your gut bacteria eat what you eat. Feed them a diverse range of fiber, and they take care of the rest."— Fiber Fueled
Fiber Fueled by Will Bulsiewicz is a science-backed guide to gut health showing why plant diversity and the F-GOALS framework can transform your microbiome and overall wellness.
