Most of people track their fat loss progress by weighing. Weighing is not the criteria to determine the progress of your fat loss. Our body weight is equal to the sum of adipose tissue, skeletal muscle, bone, and visceral organ masses. So the weight loss can be due to the muscle loss and mostly cases it is due to muscle loss only.
Our priority should be to preserve our muscle mass and target should be on fat loss. One of the common underlying principles on weight loss programmes is based on a low carb diet, at initial stages the weight loss is mainly due to the water loss. One might lose weight but the body fat % can be identical, if you lose 25 pounds but the body fat % remains same then definitely you have lost a good amount of muscle mass. People are more concerned about the numbers on the scale but there is a big difference about the weight loss and fat loss.
Gaining muscle mass has a lot of benefits such as more mass related to increased mitochondrial density therefore fat loss will be more efficient. Our metabolism is dependent on our muscle mass. If we lose muscle then our metabolism will also drops down and fats loss will be less efficient.
The best way to gain muscle is through weight training, by not starving ourselves and consuming optimum amount of calories. Body composition gives us the better idea about the percentage of muscle mass, water, fat. There are various methods to determine our body composition such as dexa scan, bioelectrical impedance etc. So don’t follow the scale as it can mislead you.