High fiber diet....

Not a Medical Doctor yet but working on it.....

 

This whole fiber thing is another blown out of proportion marketing thing though.

 

It won't make you stronger or leaner.  All it "supposedly" does anyway is clear out the digestive tract through physical friction like sand paper which "supposedly" scrapes the colon walls  to free of older undigested stuff and allow for better absorption of more recent nutrients flowing through the system.