Eat More Fiber, Feel More Energized — Here’s The Science
Most of us think of fiber as a digestive aid—great for keeping things, well, moving.
But according to Stanford professor and protein chemist Daria Mochly-Rosen, Ph.D., its benefits reach far beyond the gut. On the mindbodygreen podcast, she explained that fiber is also critical for keeping our mitochondria, the “powerhouses” of our cells, running efficiently.
These tiny organelles don’t just produce energy; they regulate how cells communicate, repair, and respond to stress. When mitochondria function well, we feel energized, focused, and resilient. When they falter, fatigue, brain fog, and inflammation often follow.
And surprisingly, what we feed our gut has everything to do with how these microscopic energy engines perform.
The hidden link between fiber, the gut, & your mitochondria
The fiber we eat doesn’t directly fuel us; it feeds the gut microbiome, which then produces compounds that fuel our mitochondria.
“When we eat enough fiber, we feed the bacteria living in our gut,” Mochly-Rosen explained. “They convert it into a compound called butyrate, which directly nourishes the mitochondria in the lining of the gut.”
Butyrate is a short-chain fatty acid that acts like rocket fuel for intestinal cells. It helps mitochondria in those cells produce energy efficiently and strengthens the gut barrier, the thin layer that keeps harmful bacteria and toxins out of the bloodstream.
Without enough fiber, your body makes less butyrate. That means less fuel for your gut’s mitochondria, a weaker barrier, and a higher risk that unwanted microbes and inflammatory molecules can slip into circulation. Over time, this can contribute to fatigue, systemic inflammation, and even chronic disease.
So yes, fiber is essential for regular digestion, but it’s also key for protecting your mitochondria, supporting immunity, and maintaining long-term health.
Feed your mitochondria
Supporting your mitochondria doesn’t have to be complicated. Small, consistent choices, especially when it comes to fiber, can make a powerful difference.
Here’s how to start:
Prioritize diverse, plant-based fiber
Different bacteria thrive on different fibers. Aim for variety—beans, lentils, oats, berries, leafy greens, seeds, and root vegetables all contribute unique prebiotic fibers that fuel a balanced microbiome.
Hit your daily target
Most adults only get about 15 grams of fiber per day, but research shows women should aim for at least 25 grams and men for 38 grams daily. Increasing intake gradually helps your microbiome adjust and reduces bloating.
Support butyrate production
In addition to fiber, foods like resistant starch (found in cooked and cooled potatoes, green bananas, and oats) are especially powerful for boosting butyrate-producing bacteria.
Consider supplementation
If it’s tough to meet your fiber needs through food alone, a high-quality fiber supplement can help bridge the gap. Here's how to up your fiber intake by 62%.
Pair with protein & polyphenols
Mitochondria also thrive on amino acids and antioxidants. Pair your fiber with protein-rich foods and colorful produce to protect mitochondria from oxidative stress and support repair.
The takeaway
Mitochondria might be microscopic, but their impact is massive. They’re responsible for everything from energy production to immune signaling, and what you feed your gut directly influences how well they perform.
“Fiber isn’t just about digestion,” Mochly-Rosen said. “It’s about supporting the bacteria that, in turn, support your mitochondria. It’s all connected.”
The next time you build your plate, think beyond your macros. That extra serving of lentils or handful of raspberries isn’t just helping your gut; it’s fueling your body’s cellular engines and protecting your long-term vitality from the inside out.
