We might be in a recession, but we can still rely on one thing: gym membership will have shot up in January. And despite these uncertain times, another given is that, as February half-term arrives, most of us will have given up going. It's no wonder - gyms are boring, expensive and the last place most of us want to be after a day of work or looking after the kids.
The other frightening fact is that in 40 years' time 90 per cent of our children will be obese, and we are the ones causing it. We all know what lies ahead, which is probably the reason we make that half-hearted attempt on the treadmill every year.
This fact is also the reason our governments have just launched their usual New Year obesity drives. In Wales, it's a 10-week weight management programme for 2,000 children and their families. In England, it's a Wallace and Gromit ad campaign that shows us we've all become fatter because we go to Tesco instead of hunting for our groceries.
The 2007 Foresight report into obesity judged the crisis to be on the same scale as climate change. Our increasing dependence on the car over the past 30 years has encouraged a more sedentary lifestyle. In short, our environment has become obesogenic (tending towards obesity), and unless we change our ways at the most basic level, we face a Pounds 50 billion medical bill and a public health emergency.
Treating the symptoms is not going to cut it. So why do we sign up to short-term weight loss programmes when more than half of our children are still driven to school every day?
One in five cars on the road in the morning rush hour is on the school run - often a distance of a couple of miles or less. While we may curse the congestion, we are the ones clogging the roads.
And when the kids come home, we allow them to sit on their computers because we don't feel that the streets are a safe place for them to be.
As a busy working parent, it isn't always possible to walk the kids to school every day, but making an effort to leave the house 15 minutes early three times a week not only ticks the exercise box and saves the stress of parking, but also gives you invaluable time with your kids. For older ones it's a chance to socialise on the way; for younger ones like my under-fives, all you need is a pram, buggy board and waterproofs.
A morning stroll sets you up for the day and does away with the nagging guilt that you should get to the gym after work. It offers children a perspective on life that isn't through the car window, by calling into local shops and chatting to people. Perhaps most importantly, it builds good habits for the future and makes kids think twice before asking mum or dad for a lift 10 minutes down the road.
But while governments launch campaigns to make us feel they're doing something practical, they fail to provide the environment that would help more families make sustainable changes to their lifestyle.
Very few roads are a pleasure to walk on because of narrow pavements and a lack of safe crossings, and schools are burdened with red tape when it comes to encouraging physical activity. Those that do apply for "safe routes to communities" funding have to write their own travel plans to qualify, a task for which many have neither the time nor the experience.
In Scotland, every local authority has a school travel adviser, but in Wales the service is patchy. Walking buses - where children are met at "stops" near home and escorted to school on foot by volunteers - are growing in popularity, but rely on enthusiastic parents and teachers to succeed.
Herein lies the solution. Parents are a powerful lobby that could make a huge difference in helping teachers to fight obesity. Imagine the impact if all those drivers who do the school run were to pressure local authorities to operate more walking buses and provide safe routes to school. Not only would walking and cycling increase, but we would also be cutting urban congestion and reducing air pollution.
The Assembly government has failed to grasp the impact that walking to school could have on reducing the obesity problem. All kids have to go to school, so it would be the perfect target if government departments worked together.
Unfortunately, the health department has its sights fixed on another round of NHS restructuring, the transport department appears preoccupied with improving links between North and South, and the Sports Council for Wales - the body charged with increasing levels of physical activity - is focused on ensuring that we get a respectable number of medals at the 2012 Olympics.
Obesity and its impact on future generations will not be solved by ad campaigns and short-term weight loss programmes. The solutions aren't complex. Helping families return to basic everyday principles, such as walking to school and buying simple food in our local shops, would be a good starting point to a healthier lifestyle for all.
On this issue, we simply can't afford an approach that's about as sustainable as signing up to a gym.
- For more information on Walk to School Week (May 18-22), see: www.walktoschool.org.uk
Felicity Waters, Freelance journalist and parent determined to walk her kids to school.