I have just had a glimpse into why. Two weeks ago after a strenuous bicycle tour I decided to ditch my longtime exercise and diet regime for a week, and what happened then surprised me.

The longer I stayed in bed the longer I wanted to stay in bed, and in fact I found rising at 7am harder than at my usual 5.15am. And the longer I stayed in bed, the more weary I felt. But it was the relaxing of my diet that had the most unexpected impact. I'd have some packet chips, a piece of cake, salted peanuts, a pie, ice cream, my wife's slice, and the more I ate of this the more I wanted to eat. These foods seem to create their own hunger.

I've put on a couple of kilos, not much I suppose but I can see how this life would add 30 kilos. Why would it stop at 30? The one week of rest became two weeks, and might even be moving into the third as you read this. I can see that a junky diet is the easy option. We all know that staying in bed is easier than getting up early to go exercising, but do we all understand that a junk food diet is the easiest for much the same reason? Just as staying in bed is easier because we don't have to do anything, eating junk food is easier because we don't have to do anything. Little or no preparation, the kids like it, same week in and week out, and there's always some on hand to quell the smallest pang. Many people will not know how to change this lifestyle and diet.

Australia has food-labelling requirements and periodic promotion of healthy eating but these measures are not achieving anything and I cannot see that they will. Do you agree with me that obesity has become the default position? What can be done?