1. "How much weight did you lose?"
Asking someone his or her weight is rude and invasive and it downgrades the immense effort it took to create the weight loss to a simple number. Think of it this way: how much someone has lost is as private as their current weight, age or salary.
2. "You look so good...I didn't recognize you."
When making small talk at holiday parties, don't tell someone who has lost weight how amazing they look. That implies they looked terrible before. It implies the person looked bad before. Seriously. Don't go there.
3. "Aren't you done yet?"
Losing weight and maintaining that loss is a process that has a beginning and never ends. This comment minimizes that process making it seem more like a project. The reality is, eating healthfully should start early and never end.
4. "You should have done this years ago."
Don't assume someone who just lost a lot of weight didn't care before or hasn't been tormented by your the inability to lose it earlier. Making positive changes is always better late than never.
5. "Good for you... I hope you'll keep it up."
This throws an element of doubt into the conversation, as if the so-called friend is skeptical about whether the weight will stay off. The only response to such a comment is: "I've never felt better, so why would I want that to change?"
6. "You look amazing -- what's your secret?"
It wasn't a special powder or magic spoon that created the weight loss; it was mindful eating and discipline.
The bottom line: success is not about the quantity of pounds lost, but instead, the quality of the knowledge gained along the way of dropping those pounds. In fact, the number of pounds on the scale does not reflect what your body is composed of; even someone who is at their ideal weight may not be in an ideal state of health.