With the change in the season our body's wt. loss pattern also changes.In winter we noticed a put on.This is the inbuilt capacity of our body. so, don't blame yourself. During winters our body starts storing fat as a layer just beneath our skin to fight against cold. As metabolism slows down and the activity level is also at the low, our body warms up by increasing our appetite and thus generating heat from what we eat.To combat overeating we must keep ourself doing some physical exercises at a regular basis.