Why does my target weight change?
When you enter your target weight at the beginning of the sign-up, it may be quite far from where your current weight is.
What the app does, is lower your target weight incrementally, until you reach your desired goal. This way, you lose weight in a slow, healthy manner, instead of too rapidly.
A quick weight loss usually makes it harder to maintain the lost weight long-term as the metabolism slows down to survive long phases without a sufficient energy supply. It's considered healthy to lose around 500 grams per week, as quicker weight loss doesn't mean quicker fat loss. It's rather an indicator that calories were reduced too strictly which resulted in muscle breakdown and water loss.