That depends on all sorts of things: where you lose your weight first, how much of a calorie deficit your 'healthy diet' is giving you, how many calories you're burning when you exercise, and what your metabolic rate is like. For some people it could be two weeks and for others two months. It's impossible to say. You'll have to start your diet and your exercise regimen and then let us know
p.s. Someone posed a similar question in the Support forum and you can see from the many different answers that this is impossible to answer definitively.