Alternative carbs such as tiger nuts and konjac can benefit fit bodies.

Resistant starches are so called because they essentially bypass (or resist) digestion in the small intestine and make it to the colon where they ferment and feed the healthy bacteria, says Grace Liu, PharmD, a San Francisco-based functional medicine specialist who helps endurance athletes improve their microbiomes. This supports both our metabolism and our immunity, she says. What’s more, adds Liu, research shows consuming various types of the starch can improve insulin sensitivity, as well as crowd out bad bugs and reduce inflammation.

It's best to consume resistant starch in its cooked form since raw starch can reduce protective bacteria like akkermansia, which is associated with leanness, and bifido longum, which is tied to longevity, says Liu.

Here, she weighs in on six of these alternative carbs and how to prepare them.