Hi Amy. Aw that’s a tricky one.
you do need to stick to the pre- op diet completely.
However the recc’s are no more 1000 calories and 100g carbohydrates daily. So on that one day if you were able to make sure your overall intake was within those guidelines you would be fine.
with the chicken salad for example a very healthy grilled chicken breast and mixed salad leaves can be under 250 calories (depending on size. ) Change that to a fried chicken one with higher calorie ingredients like sweet corn, avocado , pasta or rice salad etc and the calories would jump up. Only you can gauge what’s on the plate
you could use an App like MyFitnessPal to add things up for that one day and make sure you stay within the guidelines
No alcohol tho – this will undo the liver reducing effects of the diet xx
Hope this help and good luck xxxx