People that go from fat to fit seem to develop a god complex and think they are holier than thou.
They don't shut up about their new "lifestyle" and feel they are qualified to give absolutely everyone advice.
Most fit people I know always give out advice and what "works"......and of course it works for everyone because it worked for them.
Don't give advice unless asked. Let people live their lives the way they want. You aren't "inspirational" because you are in shape.