Just about everyone experiences a slump in the afternoon - you know that time between 2:00-4:00 PM - when you feel like the only thing that can help is another cup or coffee or a big serving of sugar or carbohydrates.
If you cannot take a nap, a better idea than reaching for that cup of joe or candy bar, is to get outside and do a quick workout of 10-20 minutes. This is even more important in the winter time - get outside and feel how the cool/cold temperatures and the winter sun can energize you.
Weight loss is all about changing your lifestyle. If taking a walk replaces that afternoon latte or sugar loading, you might see that the weight scale becomes more a friend than a foe effortlessly.