Вот нашла на кетофоруме. Говорят, что такие колебания веса нормальны:What will my weight loss progress look like?Results vary, but you will typically go through three phases1.Honeymoon: Lots of weight comes off fast. This is water that was tied up with glycogen. Note: if you don’t experience rapid weight loss in this period, do not despair. Not everyone is so lucky, and men may be more likely to see rapid initial weight loss than women.2.Keto Adaptation: Water and glycogen find a new balance and this causes a stall or even weight gain, which lasts for a week or two. Relax, this is both normal and temporary.3.Fully keto-adapted: After 3-4 weeks the body is burning fat as its main fuel and the brain has switched to running on ketones. A bumpy downward trend in your weight will begin. The trend is "bumpy" because there will be days or weeks when your weight stalls, or even goes up slightly. This happens to everyone, on every kind of weight-loss diet. Please don’t post to /r/keto that you gained a pound or two, or plateaued for a week. The trend will be especially bumpy if you are female. In particular, shark week will play hell with your scale weight.If a plateau lasts more than a couple of weeks, you may need to make adjustments to your lifestyle to break it. See the plateau section.