A waist trainer or bodyshaper does not work like magic in order for you to lose belly fat and weight in general you need to add other key factors.
Reduce your belly by making changes to your eating habits. Eliminate extra calories, especially from refined grains, sugars and saturated fats. These include snack foods, sugary sweets, soda, white bread, fatty cuts of meat and full-fat dairy. Instead, fill your plate with healthy, whole-food options such as lean meats and poultry, fish, fresh produce and whole grains.
When people do lose weight while wearing a waist trainer , it's only because they've trimmed their calorie intake.