Just my personal opinion and some knowledge i have gain from some pro. Like chad waterbury and bob chic ever mention about having a decent slim waist u must avoid crunches or any abs exercise that can achieve hypertrophy, and u gona have a bloated look (i experience it myself, my stomach is more protruding than my chest). So wat u need to do is some exercise to maintain ur abs, like plank, side plank and etc.