I loooove non-fat yogurt and kefir. And I know why: the less fat it contains, the more sour it tastes, and I have always loved the sour taste (I can eat a lemon or a whole bag of fresh cranberries in one go). I do not find full-cream (that is how you say, right?) kefir tasty because the fat masks the sourness. So I buy fat-free, but purely, purely because of taste.

I also prefer the taste of 2% milk to full-cream. I have tried them all and 2% wins. Why - I do not know, but I go by the taste.

I do not think the word "gluttony" applies, because I am having a hard time applying gluttony to apples or paper-thin crackers. To me gluttony goes with, I do not know, ... lots of ice-cream.

I also do not think that it is "gluttony" because "overeating" is SO food- specific. Gravenstein apples, yes. Wonderful dark chocolate, no. Milk, very occasionally. Kefir (=fermented milk), never. Why? No reason. People who overeat in the general sense of this term usually consume everything in sight, rather than a very particular rare variety of apples and only that variety and only during that one month in the fall when said apples are in season.

And yes I recognize that I can say NO but I just want to do what I want. Because life is already too hard, my job is boring and below the level of my skill but I have to perform it - that is enough of doing things that I do not want to do.

Why do you use the terms "gluttony" and "greed" applying them to yourself? You are UNDERweight, you should be COMPLETELY free from the compulsion to apply morality terminology to food. You are already doing well refusing foods with some ingredients taken away (I realize that my preference for sour yogurt is rare and in general full-cream is better); do even better by dropping anything that smells of morality (the word "greed" does!) from your food discourse.