Oh man
Tl/dr- Its cause it doesn't work quite that simply, and its probably water weight etc.
I think most people, especially those with ed's doing cico, tend to veiw their bodies like a machine- one where you stick In food, and if it's too much it stores as fat. Or the other way around- you put in too little food, and you start using energy stores and loose weight. But the truth is, thats a really simplified way of looking at it. Loosing weight, and using fat for fuel (lypolysis), is a really complex process, and you won't see imediate results on the scale (even though your body is likely dipping into it's energy stores rn).
I assume you mean on your period? Most people retain a lot of water on their period- I lose about 4 pounds sundenly like clockwork on the 3rd day.
There no rhyme or reason for it, there's just so much going on inside you that sometimes you just need to hang on to that extra water.
Try not to stress about it. Make sure your drinking water, and try Powerade (even if it's Powerade zero) cause when you fast you won't be getting the electrolytes (like salt and potassium) you would get from food.
Of course it's best if you don't fast for a long time, as it can cause real problems down the road.
