Try a lighter mayonnaise - I find the totally fat-free ones to be rather disgusting (weird viscous texture) but some of the calorie-reduced versions aren't too bad. And then just start to use LESS. At first, your sandwich fillings may seem a little drier and less "rich" but you can add different ingredients to them to compensate i.e. finely diced celery or dill pickles or shredded carrots, all work well as an addition to tuna salad.
Or, have your salad with full fat mayo and reduce your portion size and/or skip the bread. Instead of making a sandwich, scoop it up on celery sticks. Or use half the bread as usual - toast it, top with salad open-faced style, maybe dust with some parmesan cheese and stick under the broiler for a minute.
Goal 1 - break 200 (46 pounds lost)**DONE**
Goal 2 - leave obesity behind (BMI 29.9, at 185#) **DONE**
Goal 3 - BMI = Normal (154# or less)
| current weight: 164.0