According to theory, our ancient ancestors thrived as hunter-gatherers tens of thousands of years ago, before Nike, Cap'n Crunch, and Healthy Choice meals.

Apples' soluble fibre, pectin, improves insulin resistance, lowers cholesterol, and slows digestion. 

Bananas contain potassium and two types of fibre: pectin, which aids digestion, and resistant starch, which feeds gut bacteria.

Eat more beans. Fiber-rich black beans improve intestinal barrier function, or the body's ability to fight disease-causing compounds.

Brussels sprouts, broccoli, cauliflower, radish, bok choy, mustard greens, and cabbage are mustard vegetables.

Chickpeas can be roasted, added to salad, or crushed for hummus.

Salmon and sardines are protein-rich and support gut health. Omega-3 fatty acids have been linked to cardiovascular health, mood regulation, and inflammation.

Sauerkraut, kimchi, and pickles offer non-dairy probiotics, says Binder-McAsey.