Courtney Roselle, NASM-certified personal trainer, certified functional strength coach, and founder of Iron Grace, told POPSUGAR that, when it comes to working your abs, you really need to focus on nutrition (speak to a dietitian about that specifically). Ultimately, you need a low enough percentage of body fat to see your abs and in order to do that, you need to be in a caloric deficit. Dietitians have also told us in past interviews that, when you're looking to build your ab muscles and lose weight, you should be eating enough protein. Read more on food choices to promote weight-loss and ab visibility here.
You need to incorporate strength and weight training to build your core, Courtney said, because sit-ups alone won't cut it. "It may come as a surprise, but the number one ab exercise I recommend is squatting. When you start to squat heavy, you fire up your core muscles to lift the weight and keep your body stable," she said. "You should also incorporate flexion-extension movements like burpees and isometric holds like planks." Check out more trainer exercise tips for abs here.