fluid, fat, glycogen loss and detox plus cell cytoplasmic fluid is consumed
I tend to loose mass everywhere at the same time. My usual BMI is 18.5 -19 and my fat percentage - about 26%. My cheeks run out of fat easier, since I have not much there anyway, but my stomach keeps it longer than legs and buttocks, which account for fast decrease in cloth size.
I feel I loose also a lot of fluids - water bind to minerals and or toxins, which accounts for some of the faster weight loss in the first days of fasting.
Muscles size tends to decrease as well - the fat between the muscle fibers is also burnt, together with the muscle glycogen and the water binding it, as well as some fluids from muscles too.
Overall the size (as opposed to number) of the cells decreases in all tissues, given enough time, with the internal organs spared up until starvation phase, unless breaking the pathological tissue plus healing is under way in them.
This is beneficial, since the internal fluids of the cells get renewed as well - hopefully with good nutrition after the fast.
- starvation takes really long to begin in a normally nourished individual -