Marisa Mackle: 'Fat at 40? Where's the fun in that?'

This year myself and my son, Gary, spent Christmas in Spain. I didn't think I'd indulge too much because it's sunny on the Costa del Sol. Salads are easier to eat, and drinking lots of water isn't half as boring as it is back home in Ireland.

But of course I couldn't inflict a salad on my growing, skinny son on Christmas Day, so we booked into a lovely restaurant where every dish seemed to be about 7,000 calories.

Still, it's Christmas, I said to myself, as I tucked in, and I also reminded myself it was Christmas while enjoying my brandy pudding. When we got back to our apartment I duly left out mince pies and whiskey for Santa. Of course these were gone by the morning - and so was my waistline.

Gary, naturally, was most anxious to share his sweets with me. I happily obliged and we demolished a bumper box of chocs. I stepped on to the scales the day after Stephen's Day and nearly cried. I was up four pounds.

Yes, four pounds in just two days. I felt ashamed for pigging out in the name of the Lord. Jesus' birthday should not have given me the green light to gobble everything in sight for 48 hours. Honestly, where was my self-control?

I started my diet on December 27. It was sunny and we went for a walk on the beach. Afterwards Gary had ice-cream. I did not. I replaced my nightly glass of wine with a soda water.

That was a few days ago now. I got off to a flying start, losing four pounds during the first few days. Of course that was great, but the boredom kicked in very quickly.

Being away in Spain and not drinking is a chore. Everywhere you walk, there are people sitting outside cafes drinking wine and beer.

Sometimes even in the mornings. It is very hard to march past them with determination, carrying grocery bags, which in my case consisted of water, eggs, tofu and grapefruits.

I had brought some diet magazines with me because I knew my weight-loss programme would begin straight after Christmas.

I thought the magazines might be inspiring, but they managed to make me feel hungry. Page after page of recipes and ads for low-fat treats made my tummy grumble loudly.

Even the cover girls' personal stories weren't that encouraging as they were all under 30 and I am over 40, which makes losing weight harder.

Oh, there was a time, when I could dance for a whole weekend, surviving on ciggies and vodka and diet Coke. I was a twig. But God, so unhealthy. This time I'm sticking to a high-protein, low-carb vegetarian diet.

It's worked before and it's working again. I'm now down half-a-stone. Of course, when Gary resumes school it'll be tough and I'll have to resist the Danish pastries when I meet the other mums for morning coffee. As some politicians have been know to say, a lot done, more to do.