Hello, abdominal suction is an action that can exercise transverse abdominis, but the real reduction of stomach (weight loss) is brushing off fat. Many people think that doing some abdominal exercises can slim down your belly, but this is actually wrong. There is no local reduction in weight loss. There is a simple reason. Imagine, is there only 6 clearly visible abdominal muscles in the abdomen? It's not realistic. If you don't lose pure fat, and then do abdominal exercises blindly, the muscle mass is getting bigger and bigger, but if you don't lose fat, it will only make your stomach more and more bulging.
Thin belly suggested doing aerobic exercise combined with abdominal exercise, then working hard on diet, eating more fruits and vegetables, and abstaining from drinks.
I hope the above is helpful to you.