Can hypnotherapy help to change my tastes in food?
As a professional hypnotist, I would start by asking you to consider if your body perhaps needs one or more nutrients in those snacks, or maybe there is a component of salad that really doesn't work for your body? There's the possibility of aversion to salad due to a negative association at some point in your life, say as a child you were forced to eat it. And of course there's the positive association of lardy snacks that the salad has to compete with! Sugar and fat are powerful motivators. 

I don't think any respectable hypnotist would set about 'making' you like or dislike anything without seriously considering the ramifications of such an approach, and I doubt that hypnotic suggestion would be enough to overcome the messages coming from your enteric nervous system in the case of it not being an emotionally-based negative association.