Since the Les Mills Core is only 30 minutes, we would recommend attending two or three times each week for maximum results.
If you're trying to lose weight whilst toning the core, add some cardio and strength training into your fitness routine to help burn fat. Otherwise, you may find that the core work you're putting in during your Core class doesn't show as well as you'd hoped.
After your Core class, it's best to avoid further resistance training to allow your body some recovery time. This is where a cardio session in the gym will work well.