I vote live feedings. Normally sparks them into eating. For example:

Male spider 1 year old 700 grams was bought from someone who only fed 1 f/t mouse a week and would "only eat f/t over night b/c he won't strike". He stopped eating for me for about 3 weeks, so I decided to put him on live like everyone else. And lone and behold this the snake who can't strike and only ate f/t gobbled the mouse down in a matter of minutes.

If the snake starts loosing weight another option is ASF rats or Gerbils.