High ketone lvl in urine

4 months ago I started the keto diet, I have had very good results, this has motivated my younger sister to try the keto diet, the thing is that she started a week ago, but when measuring her ketone levels with urine keto strips, the results are too high for a person who has been doing it for 1 week, does anyone have any idea what happened?

She is 28 years old, weighs 71 kgs, is 5'4" tall and works as a painter and exercises 3 days a week.