What food is like a power wash for your interior?

 Linseed and Chia seeds.

They are 50/50 soluble and insoluble fibers and when immersed in water, they become very lubricious. All of this adds up to "sweeping and mopping" the digestive tract.

Soluble fiber dissolves and forms a gel that lubricates. Insoluble fiber acts like a broom, attracting debris and sweeping it away. Together they form a team of cleansers for your body.

Chia is also delicious as a pudding by adding coconut milk, a little fruit, and letting it sit overnight in the fridge.