Limiting eating out to the odd treat is a good way of preventing restaurant food from tipping your calories intake above your recommended daily allowance. If you love the sociable aspect of eating out then you can still get it by having people round for a healthy dinner instead. You might even save money by doing this.
However, there are restaurants that cater for people who are trying to enjoy a very healthy diet. The key is to do your research so that you know exactly what you are taking in. Restaurants are becoming more transparent about things like the calorific content of their meals so you can pick and choose if you want to eat out regularly but you still want to achieve a certain level of weight loss.