The scale reading seems implausibly low, very implausibly low, but it doesn't really matter. The exact figure isn't the problem per se, the problem is that the figure is never going to go down. She's had eighteen months of ominous medical episodes that she's completely ignored, and beetus is just another brick in the wall.
People in this thread have said she'll live for years yet, and yet we've just seen her treat diabetes with a juice fast, which is analogous to trying to put out a chemical fire with vodka. I think she's going to tard herself to death before her 40th birthday, frankly. Beetus isn't like her existing health problems: she can't just ignore it and cross your fingers; you treat diabetes or you're maimed and killed by it. If it doesn't do her in, it'll only be because something else did first. The scale would only be truly accurate if the reading said "DEATHFAT".