As long as the body can bear it, it will not affect health. It won't be so thin all the time, but it will be much thinner if the base is large. I started to lose weight quickly when I took diet pills, and then I slowed down. The body will adjust itself, not just how much it has lost in a few days. It is normal to have fluctuations during the period, or it depends on the final effect of a course of treatment.