It is important to keep as active as you can, but this does not mean that you need to do hours of exercise a day.  All it means is to say goodbye couch! and move more. Now, whether that is, walking down to the shops instead of driving or playing catch or football with the kids outside or walking during your lunch break or taking the dog for a walk everyday.

The more you move the more energy you are using and burning up. This energy is not getting stored in your body and instead of your weight increasing because you are sedentary you find your weight decreasing due to increasing your energy output.