Think of winter snacks the same way you think of a cozy fireplace. You need kindling to get the fire started, smaller logs to provide intermediate fuel and larger pieces of wood to keep the heat coming for hours on end. A little sugar is kindling, carbohydrates are the intermediate fuel and protein is the long burning log. Graham cracker PBJs provide all three. Keep in mind, however, that -- as with granola bars -- you need to watch the ingredients. Some peanut butters are packed with unhealthy and unnatural additives. The same is true of jelly. Look for a short list of ingredients with little or no added oils, sugars and preservatives. Otherwise, eat up, warm-up and revel in the knowledge that you are filling your stomach without enlarging your belly.