After you've lost a substantial amount of weight: 10 to 15 pounds, you'll really notice the difference in how you feel. The changes in your appearance will be obvious without pulling out the ``before'' picture and comparing. You may be surprised and/or disappointed to discover that people you encounter every day don't remark on the dramatic change you perceive. There are several reasons for this, and it's nothing to get upset about.
It's hard to notice slow, gradual changes. You have the advantage of being inside your body. You can feel the difference in how you move, how your clothes fit, and how much energy you have. Others have only your appearance to go by, and that's often limited to your face and hands. While the difference would be obvious if they compared a picture from a few months ago with your present self, your slow, steady progress may go unnoticed until some day somebody looks at you, startled, and exclaims, ``Hey! Didn't you used to be fat?''
When people do notice a change, many will react in the time proven and honourable manner of minding their own business and keeping their mouths shut. Politeness and consideration are usually the motivation. How would you feel if you noticed a friend seemed to be slimmer and you blurted out at lunch, ``Hey, haven't you lost some weight?'' And then he quietly said, eyes averted, ``Well, no actually, I haven't.''
Don't worry, eventually they will notice.