You shouldn't let people know you're on a diet. That's like saying you're in a relationship after only 4 weeks of dating. It's embarrassing if and when you fail. Instead, let people see the results for what they are - results. "Sam Smith lost a lot of weight" or "Sam Smith got into shape" is a lot better than "Sam Smith is on a diet" *six months later he's still the same size*
Let the proof be in the pudding.
