This week’s Fitness Secret: How to get a Flat Stomach!! Drink at Least 8 Glasses of Lemon Juice Water. Eat 5 – 6 small meals a day instead of 3 big meals. Do 100 reps of various ab exercises per day. Do 30 minutes of cardio 5 times a week. Do 30 minutes of plyometric 5 times a week. (jumping jacks, squat jumps, push-ups etc) Eat more fruit and vegetables.