You have to do a heck of a lot of exercise to burn off the calories in even a small snack bar. Don't get me wrong, exercise is good, but don't rely on it for weight loss. Unless you are active all day then IMO you are unlikely to notice much weight loss in what you pack in to the 3 times a week exercise session.
However you may build muscle which raises metabolic rate, and should eventually get toned to have a better silhouette. Not to mention getting fitter/healthier.
Yes exercise can allow you to eat more for a set weight loss, but not a lot more.
IMO you would do best to keep the exercise up, but also keep track of what you are eating to ensure you are burning up more calories than you are taking in each day.