If you need to loose weight, remember, all unburnt calories get converted to fat, so eat less than you need and do some exercise.
Also insulin levels go up when you eat food, insulin tells your fat cells to store energy, so when insulin levels are low, your fat cells are converting fat into energy, ie the fastest way to loose fat is to exercise on an empty stomach after waking as that is when insulin is at its lowest, however I don't recommend it as it can make you dizzy. Maybe just do gentle walking on empty stomach, or eat a small amount of carbs beforehand.
what has any of this got to do with dry fasting ??