I use regular mayo, I hate low fat mayo anyways.
I do not measure it or anything. Usually everyday I made a chicken salad with real mayo in it and I just put in however much I want until it is coated (which is certainly more than 1 T, maybe 1/4 cup?)....and I have been loosing weight just fine so far
Of course that is the only thing I use it with but I don't measure any of my fats like olive oil, etc I just use however much I need and don't fret about it, doesn't seem to be hurting me any with weight loss, pants I could not fit into last week fit me this week.
Skinnymini