This is where understanding your macronutrients comes into play. Because you can control exactly what goes into your body when you cook on your own, you can learn how to make room for your evening out.
Training the core involves conditioning and weight training. Finding a nice blend between the two will get you abs that not only look good but are also strong. It is so crucial to have a strong core, even if you are not an athlete. Your core makes up a large part of your body, and works directly with the muscle groups around it.