Fat loss is much quicker than muscle gain
A kilo of muscle requires 4500 calories, sourced from protein, after enough stress has been applied to the muscles
Problem is the body uses 30% of protein calories for digestion
So if you ate 1,125gms of protein, say over a week, 30% of those are gone, leaving you well short of a kilo of muscle, actually 330 gms of protein short.
So you eat the extra 330gms of protein, only to find another 110gms have gone towards digestion, still short after 1565gms of protein.
To lose 1kg of fat you need to burn 9000calories over and above what your body needs as maintenance
So a workout burns between 300-500 calories, depending on various factors. Three x week is 1500 calories burnt, but not all are sourced from fat, glycogen stores in the muscle are used first
So those that claim to lose 5kg of fat in a week are really, really bad at maths, thats 45,000 calories burnt or not eaten in a week, good luck lol
Its 90% water
Fat loss is still much quicker than muscle gain
Notice I didnt say weight loss and weight gain