Simply starts to eat alternative snack items -- like yoghurt (6)
I believe the answer is:
easily
'simply' is the definition.
(thesaurus)
'starts to eat alternative snack items like yoghurt' is the wordplay.
'starts to' indicates taking the first letters.
The initial letters of 'eat alternative snack items like yoghurt' is 'EASILY'.
(Other definitions for easily that I've seen before include "With little difficulty" , "Simply" , "Without difficulty or effort" , "Effortlessly" , "without doubt" .)