Of course you'll lose weight in the early days.
- Bloat. Perfectly normal.
- It's a crash diet. 800-1200 cals for 9 days is incredibly unhealthy. Unless perhaps you are already tiny.
Someone like Yawn is fairly tall. I'm not quite sure how tall, but I'm tall and my Basal Metabolic Rate (so calories burned staying in bed doing nothing) is 1850. I'm a fair bit thinner than Yawn too, so if I assume she's only about 2" shorter then based on her current size her BMR is going to be even higher.
The thing is, I don't lie in bed all day. Realistically my calorie burn is between 2200 and 2700, depending on how active I am. Consuming only 800-1200 calories for 9 days would be incredibly unhealthy.
So promoting that diet and using words such as thinspiration in said promotion is incredibly dangerous. Combine that with her gradual weight gain over the years (not as obvious because she's good at using the right angles to make herself look better) despite these frequent crash diets, she is absolutely promoting eating disorders.