Most people don't measure out a Tbsp of mayonnaise when adding to their tuna or chicken. So what happens is 1 tbsp of mayo turns into like 3 or 4 tbsp of mayo. Use it like that every day for a week and it adds up...
This.
Mayo stretches really far in egg salad, because it meshes really well with the yolks emulsifying them and creates a good consistency. 4 eggs and 1 rounded tablespoon of mayo is perfect.
However...Tuna is extremely dry and has horrid consistency. It takes at least 2 rounded tablespoons of mayo to become edible. Along with celery and onions.
1 tablespoon on one side of the toast, for a sandwich, is completely tasteless and barely covers the bread, spread on very thin. 1 tbsp adds almost nothing to a sandwich and is pointless. You could add 2 pieces of reduced fat 2% cheese instead of 1 tbsp mayo, no brainer.
To make 1 tbsp mayo worthy of a sandwich it needs to be meshed with something really juicy like a burger..Which is verging on cheat meal territory in which case anything goes so just say fuck it lol dip everything in mayo...On a basic turkey sandwich 2 pieces of 2% provolone adds much more for the 100 cals.
On a baked potato or dipping fries into mayo is amazing. I get bagged frozen fries that are basically just potatoes 1.5g fat per 3oz...I find 1tbsp of mayo enough for 9oz of fries, which is roughly 60carbs. Just caress the edge of the fry in mayo, no need to "scoop" a lot on there...A little dab will add tons of flavor to the rather neutral tasting potato.
But for potatos I generally prefer sour cream. Tons of flavor for no carbs and only 25 cals per tbsp.