This is where the real weight loss work comes in. It's not so much losing the weight, although that can be challenging for sure, but what follows that determines one's success, or lack of it, at keeping the weight off.
I think of successful weight loss as being like a three-legged stool. One leg is a healthy diet, one leg is consistent exercise, and one leg is the correct mindset. Without it, the stool comes crashing down.