WHAT do you need? You need a scale & tape measure
Every Friday, weigh yourself naked after using the bathroom before you eat or drink anything. Then measure your waist right above your belly button. Write the two numbers down.
If your weight and waist are dropping, you are losing mostly fat.
If your weight goes up and your waist goes down, you are losing almost all fat.
If your weight goes down, but the waist goes up or stays the same, you are losing weight, but that weight is not fat, it is water — or worse, muscle.