Been living like this for years, didn't know it was a diet till now

That's an 17 500 calorie deficit in 3 days, to lose 5lbs of fat in that timeframe (1lb is around 3 500 calories). Or a 5800 calorie deficit a day. A physically impossible deficit. Even eating nothing won't accomplish such a deficit. You won't lose much, if any fat on this diet, most of the weight loss will be from dehydration and drying out. So temporary. It will also make all your muscles look flaccid and flat as they will be completely depleted of glycogen on this zero carb diet. Which is usually the opposite of what you want, even for women. There's a reason why bodybuilders combine drying out/dehydration with eating tonnes of carbohydrates at the end of a carb loading phase, to make their muscles look full.