look your best bet is to leave the high gi foods alone, i have guys have a whey shake post work out and then a low gi meal an hour afterwards. if u are battling to loose belly fat u are taking in too many calories,and you arent doing enough cardio,20mins a day isnt gonna be enough,also splitting cardio and weights is best, doing 30mins of cardio daily before breakfast is best,the reason before breakfast is because your insulin levels are low and also u are less likely to skip it later on in the day. keep your carbs low for 2 weeks solid as to deplete glycogen stores, also keep your carbs to 3x a day,pre and post work out (starchy carbs) and for breakfast(starchy carbs).