Try adding four or five to the end of your workout to challenge your core a little more, or turn them into a standalone workout—try doing 12-15 reps of each exercise and then repeating the circuit (of four or five exercises) three to four times, to start. If you feel tension in your lower back during any of these exercises, stop and reset, making sure your abs are really engaged and that your back is not arched. You can also try starting with fewer reps. If you still feel discomfort, skip that exercise and try a different that allows you to keep your spine in a safer position. (It's also helpful to read up on which abs exercises tend to be irritating for lower-back issues beforehand if that's a concern for you.)
Apart from helping to keep your body-fat percentage where it needs to be, eating the right foods (and avoiding the wrong ones) will help you build a strong core worth revealing, says nutritionist Wesley Delbridge, R.D., a spokesperson for the Academy of Nutrition & Dietetics. After all, while whole carbs like quinoa, brown rice, sweet potatoes, and fruit will fuel your workouts so that you burn more calories, protein-rich foods like eggs, lean meats, and, fish will help you recover from them so that you build more muscle, he says. Unsaturated fats from almond butter, walnuts, avocado, and olive oil work to help your metabolism function at its best and your body absorb all of the nutrients it needs, White says.