Consider starch and fiber, both polysaccharides, both derived from plants, both composed of hundreds to thousands of monosaccharides joined together, but they're joined together differently, and that changes the effect  they have on your body.
Aplūkosim cieti un šķiedrvielas — abi ir polisaharīdi, abi ir augu izcelsmes, abus veido no simtiem līdz tūkstošiem savienotu monosaharīdu, taču tie ir savienoti atšķirīgi, tādēļ ietekmē tavu ķermeni dažādi.