Weight / Fat loss

My opinion* on the cycle commute is that once your body is used to the effort, you expend very minimal calorie burn.
So I'd always under state my calorific expenditure of your commute to work.
Training is a different matter.

• I am no expert!
  
  

You'd be wrong. You still have to expend the same calories to cover the same distance in the same time, it might just feel easier. Efficiency improvements account for fsck all change. Maybe if you were commuting at 40kph+ and swapped for a TT bike..