Raw food diet and gut health

A raw food diet means eating only or mostly uncooked fruits, vegetables, nuts, and seeds. The reasoning behind it usually goes that heat destroys beneficial enzymes and nutrients. Scientists finally tested cooking's effect on gut bacteria directly, and what they found is a lot more specific and interesting than a simple raw-is-better or cooked-is-better verdict. It's one of several eating styles we've looked at for their effect on gut bacteria, alongside paleo, carnivore, and vegan diets.

The first study of its kind

Plenty of research has compared different diet types before, but almost nobody had isolated cooking itself, separate from the type of food, as the variable that changes your gut bacteria. So researchers fed mice matched diets of identical foods, prepared either raw or cooked, and watched what happened when cooking was the only thing that changed.¹

Raw food contains genuine antimicrobial compounds

The raw food movement doesn't usually mention this: certain plant compounds with antimicrobial properties get destroyed by cooking, so they reach your gut fully intact when you eat food raw, and they appear to directly harm certain gut bacteria. Being natural doesn't automatically make raw food better for your gut. Raw food can actively hurt specific bacteria through a mechanism that cooking would otherwise neutralize.

Cooking changes how many calories even reach your gut bacteria

Two separate mechanisms seem to drive the difference. Cooking makes food easier to digest, so your body absorbs more calories higher up in the digestive tract, leaving less behind for your gut bacteria to ferment further down. Raw food's antimicrobial compounds then add a second, chemical layer of disruption on top of that.

The effect is food-specific, not universal

And it isn't the same across every food, either. Starchy foods like sweet potato showed dramatic gut bacteria differences between raw and cooked forms, while beets and carrots showed much smaller differences. Raw versus cooked meat barely moved the needle at all.

A strange, unresolved finding about weight

Mice eating raw food lost weight during the study. But when researchers transplanted gut bacteria from those leaner, raw-fed mice into new mice on a normal diet, the new mice gained weight instead. Nobody has fully figured out why yet, and the researchers flagged it as something that needs a lot more study.

A raw food diet is not uniformly better or worse for gut health, and that mixed picture is the real takeaway. Raw starchy vegetables in particular interact with your gut bacteria very differently than their cooked counterparts, while foods like meat and lower-starch vegetables show much less difference either way. Focus on getting a wide range of fiber-rich foods into your week, raw or cooked, and you will get more out of it than obsessing over the raw-versus-cooked question alone. The same principle holds whether you eat Mediterranean-style or something stricter.

1. Mouse study isolating cooking, independent of food type, as a driver of gut bacteria change

This content is for educational purposes only and is not a substitute for professional medical advice.