Applying Behavioral Nudges in a Dietary Comparator for Surgical Trials: Developing the MediDiet

•Dietary interventions are increasingly being proposed as alternatives to surgery.•We tested behavioral nudges in dietary feedback for intended and unintended effects.•Nudges as a class did not evoke negative reactions nor prove effective.•Specific nudges had different effects on participants' reactions.•Peer comparison and defaults may warrant further testing.