Fat Burning Calorie Deficit
If for whatever reason you are not doing enough exercise or move around more, you may start burning your excess fat by following a healthier diet and reducing the calorie intake. 
You would lose about one gram of fat for every 8 calorie deficit you create.
Say, based on your lifestyle if you require 2008 calories on a certain day, and you eat that day only 2000 calories then you have lost 1 gram of your fat.
Not easy, but all adds up, more calorie deficit, less fat around your waist!