Even our children's interest was piqued. But something still seemed to be lacking. I didn't feel confident that I could stick to my regime. I needed more. But what?

My brainwave was to involve the kids as coaches. Both my daughters said they wanted to coach dad at first. Then my eldest daughter offered to switch allegiance and be my coach. Sweet. My motivation level was rising, but I was still not motivated enough.

I had another brainwave. I wanted my kids to do something. Call me a tiger parent, if you want, but that's how it was.

If I won, the losing coach would agree to apply to a month-long international peace camp programme. (Although her sister had enjoyed the experience, she had made it clear that she was not gung-ho, and I had been holding out for a change of heart.) If I lost, the winning coach would 'get to go' to Japan to climb Mt. Fuji to raise money for Habitat for Humanity.

When I presented this to my children, my youngest screamed with delight at the challenge. She understood what I was up to.

My eldest just smiled at me, willing to wait for the future to unfold before getting too worked up about the situation.

My husband reminded me gently that our children are dissimilar in character. I know that, but my plan had so far passed the test.

He also pointed out that the organisation of the whole event was weighted in my favour.

But as he had no problem with the idea of his daughter climbing the highest mountain in Japan to raise money for a good cause, he did not object. So we were all invested. It was 'Game on!'

In the 48 hours since our competition began the following has happened: Aunty E (our beloved helper) was offered a bribe to spike my food with sugar - and she won't tell me by who.

We collectively decided that the coaches needed sufficient reward for their efforts aside from their parents' well-being.

So we all got together and decided that the winning coach would be given an honorarium.

My husband was then forbidden from eating three crackers for an evening snack.

But clever and caring as she is, his coach intuitively realised she had better let him have one. (When she fell asleep, he ate a bowl of cereal and I didn't stop him.)

Our children have frogmarched us both to the scales - twice. I had to do three minutes of jumping jacks and plank for one minute before my coach went off to school.

I mentioned in passing, that even water has weight. Bad move. As she went out the door, my coach told me to stop drinking coffee.

Actually, my husband and I are neck-and-neck in terms of weight loss. But I'm feeling confident and we are all still glowing from the various fits of giggles.

This is turning out to be so much family fun that we may end up doing it all again in a couple of years.

Karmel Schreyer is a freelance writer and a mother of two girls