Why? There's no point in reducing your calorie intake if you don't do regular, moderate exercise alongside it. Exercise burns calories, and facilitates slimming in a big way. On top of that, it strengthens your body and makes you at one with your bod, which is essential when you want to feel beautiful!
How? We're not talking about running for 2 hours in the cold and dark if you're not the sporty type! Instead, look into increasing the amount of time you spend walking (home-office-home route, shopping, walking the dog, taking the kids to the park, etc.) and give up using lifts and escalators. You could even start thinking about joining a gym, or at least get clued up about membership packages for after Christmas when you're armed with good resolutions and full of energy after the holidays!